JP3658332B2 - Semiconductor device, method for manufacturing the same, and millimeter-wave band communication device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor device in which different semiconductor elements are integrated on the same substrate, a manufacturing method thereof, and a millimeter wave band communication device.
[0002]
[Prior art]
In recent years, in millimeter wave bands (30 GHz to 90 GHz), transistors such as HBT (heterojunction bipolar transistor) and HEMT (high electron mobility transistor) are used as oscillation elements and amplifiers, and Schottky diodes are used as varactors and mixers. Has been done. Further, there are semiconductor devices integrated by fabricating these elements on the same substrate (Japanese Patent Laid-Open Nos. 3-64929 and 63-129656).
[0003]
However, in the millimeter wave band, when HBT or HEMT is used as the oscillation element, the emitter width (1 μm or less), the gate length (0.2 μm or less), etc. are required in order to cope with higher frequency transistors. It is necessary to reduce the parasitic capacitance and the parasitic resistance due to the above, and this is a complicated process, so that the yield is reduced. Further, when the emitter width and gate length are miniaturized, there is a problem that the amount of current becomes small and it becomes difficult to obtain output power necessary as an oscillation element.
[0004]
Therefore, as a semiconductor device for solving these problems, there is a semiconductor device using a diode having a negative resistance instead of HBT or HEMT as an oscillation element (Japanese Patent Laid-Open No. 1-112827). In this semiconductor device, as shown in FIG. ⁺ An electrode of TiW806 / Au807 is provided on the GaAs layer 805, and n ⁺ -An IMPATT (Impact Ionization Avalanche Transit Time) diode having a negative resistance in which an electrode of Ti808 / Au809 is provided on the GaAs layer 802, and a microstrip patch made of Ti810 / Au811 on a semi-insulating GaAs substrate 801 Is configured. Furthermore, other devices can be integrated on the semi-insulating GaAs substrate 801, n ⁺ It is disclosed that other devices can be integrated using the GaAs layer 802.
[0005]
Hereinafter, the structure and manufacturing method of the semiconductor device will be described with reference to FIG.
[0006]
As shown in FIG. 18A, first, on a semi-insulating GaAs substrate 801, n ⁺ -GaAs layer 802 (concentration 1 × 10 ¹⁹ cm ^-3 , Thickness 1.5 μm), n-GaAs layer 803 (concentration 2 × 10 ¹⁷ cm ^-3 , Thickness 0.25 μm), p-GaAs layer 804 (concentration 2 × 10 ¹⁷ cm ^-3 , Thickness 0.25μm), p ⁺ -GaAs layer 805 (concentration 1 × 10 ¹⁹ cm ^-3 , Thickness 0.2 μm) is epitaxially grown sequentially. Next, after applying a photoresist, a circle having a diameter of 5 μm is patterned to form an electrode of TiW806 (thickness 100 nm) / Au807 (400 nm). Next, by wet etching, the electrode of TiW806 (thickness 100 nm) / Au807 (400 nm) is used as an etching mask. ⁺ -GaAs layer 805, p-GaAs layer 804, n-GaA layer 803, n ⁺ -Etch GaAs layer 802, n ⁺ -Stop etching in GaAs layer 802.
[0007]
Next, as shown in FIG. 18B, a photoresist is applied, a square with a side of 75 μm is patterned, and an electrode of Ti 808 (100 nm) / Au 809 (400 mn) is formed by a lift-off method. At this time, the electrodes (808, 809) are self-aligned with the electrodes (806, 807).
[0008]
Next, as shown in FIG. ⁺ -An anisotropic plasma etching is performed on a part of the GaAs layer 802 and the semi-insulating GaAs substrate 801 (about 100 nm). This isolates the IMPATT diode as a mesa on the semi-insulating GaAs substrate 801. Thereafter, a microstrip patch of Ti810 (100 nm) / Au811 (400 nm) is formed on the semi-insulating GaAs substrate 801 by a lift-off method.
[0009]
In the semiconductor device using the IMPATT diode having the negative resistance, other elements can be integrated on the semi-insulating GaAs substrate 801 immediately before forming the microstrip patch (810, 811). In particular, the active device region can be formed by ion implantation into the semi-insulating GaAs substrate 801 away from the region of the IMPATT diode and the microstrip patch. Instead, n ⁺ Etching the GaAs layer 802 using a separate photolithography mask away from the area of the IMPATT diode and microstrip patch to produce other active devices ⁺ A region of the GaAs layer 802 that is formally doped can be preserved. The IMPATT diode manufactured in this way has advantages in that the process is easy and the output power as an oscillation element is large because the IMPATT diode can cope with the millimeter wave band without being miniaturized as compared with the HBT and HEMT.
[0010]
[Problems to be solved by the invention]
By the way, in the semiconductor element using the IMPATT diode having the negative resistance, ion implantation is used as a method for manufacturing an active element other than the IMPATT diode on the semi-insulating substrate. Therefore, the ion-implanted region is activated. Therefore, it is necessary to perform heat treatment (annealing) at a high temperature (for example, about 600 ° C.) after ion implantation. Due to this heat treatment, there is a problem that the contact resistance of the previously fabricated IMPATT diode part and the epitaxial structure are deteriorated (heterojunction deterioration, concentration profile deterioration).
[0011]
In addition, n which is a contact layer of the IMPATT diode ⁺ The GaAs layer 802 is formed to reduce the contact resistance of the electrodes (808, 809). ⁺ The mold is highly doped, n ⁺ -When the GaAs layer 802 is used to fabricate an active element other than an IMPATT diode, for example, a high-concentration n-type Schottky characteristic required for a gate electrode of a MESFET or a Schottky electrode of a Schottky diode is used. ⁺ There is a problem that it cannot be obtained with the GaAs layer 802.
[0012]
As described above, in the above semiconductor device, it is difficult to obtain desired characteristics even if a diode having a negative resistance and a Schottky diode are formed on the same substrate, and further, reproducibility cannot be obtained.
[0013]
Accordingly, an object of the present invention is to provide a semiconductor device capable of easily integrating a diode having a negative resistance without deterioration of contact resistance and deterioration of an epitaxial structure and a Schottky diode having good Schottky characteristics on the same substrate. The present invention provides a manufacturing method and a low-loss and high-performance millimeter-wave band communication device using the semiconductor device.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, a semiconductor device according to a first invention is formed by epitaxial growth on a semi-insulating substrate, and at least an ohmic electrode side high concentration semiconductor layer and a Schottky electrode side low concentration semiconductor layer are sequentially stacked. A semiconductor device comprising: a multilayer structure having key diode characteristics; and a multilayer structure having negative resistance diode characteristics formed by epitaxial growth on the multilayer structure having Schottky diode characteristics, wherein the negative resistance diode characteristics The negative resistance diode characteristic is provided in a region other than the formation region of the diode having the negative resistance in which the anode ohmic electrode and the cathode ohmic electrode are formed, and the diode having the negative resistance. A Schottky electrode is formed on the active layer having a multilayer structure The Schottky electrode having a laminated structure provided in a region other than the first Schottky diode formed, the formation region of the diode having the negative resistance and the formation region of the first Schottky diode, and having the Schottky diode characteristics And a second Schottky diode having an ohmic electrode formed on the ohmic electrode high concentration semiconductor layer.
[0015]
According to the semiconductor device having the above-described structure, the negative resistance formed by the anode ohmic electrode and the cathode ohmic electrode is provided in the laminated structure having the negative resistance diode characteristic formed by the epitaxial growth, and the negative resistance is provided. A first Schottky diode in which a Schottky electrode is formed on an active layer having a multilayer structure having the negative resistance diode characteristic is provided in a region other than the formation region of the diode having n. Furthermore, in a region other than the formation region of the diode having negative resistance and the formation region of the first Schottky diode, a Schottky electrode having a Schottky diode characteristic having a Schottky diode property formed by epitaxial growth on the semi-insulating substrate A second Schottky diode having a Schottky electrode and an ohmic electrode formed on the side low concentration semiconductor layer and the ohmic electrode side high concentration semiconductor layer is provided. Accordingly, since there is no need to perform ion implantation and high-temperature heat treatment, problems such as the epitaxial structure of the diode having negative resistance and the deterioration of contact resistance are eliminated. In the first Schottky diode, since the Schottky electrode is formed on the active layer having a negative resistance diode characteristic, a Schottky diode having a large capacitance change suitable for use in a varactor diode or the like is obtained. In addition, in the second Schottky diode, a Schottky electrode is formed on the Schottky electrode side low concentration semiconductor layer and an ohmic electrode is formed on the ohmic electrode side high concentration semiconductor layer. A Schottky diode having a small resistance component and a small capacitance can be obtained. Such a first Schottky diode having a large capacitance change, a second Schottky diode having a small resistance component and a small capacitance, and a diode having a negative resistance can be integrated on the same substrate, thereby reducing signal loss. Miniaturization can be achieved.
[0016]
The semiconductor device of the second invention is formed by epitaxial growth on a laminated structure having a negative resistance diode characteristic formed by epitaxial growth on a semi-insulating substrate, and on the laminated structure having the negative resistance diode characteristic, A semiconductor device comprising a laminated structure having a Schottky diode characteristic in which at least an ohmic electrode side high-concentration semiconductor layer and a Schottky electrode side low-concentration semiconductor layer are sequentially laminated, and the laminated structure having the negative resistance diode characteristic A diode having a negative resistance in which an anode ohmic electrode and a cathode ohmic electrode are formed, and a stacked structure provided in a region other than the formation region of the diode having the negative resistance and having the negative resistance diode characteristics A first Schottky in which a Schottky electrode is formed on the active layer of On the low-concentration semiconductor layer on the Schottky electrode side of the stacked structure provided in a region other than the formation region of the diode and the diode having the negative resistance and the formation region of the first Schottky diode And a second Schottky diode having an ohmic electrode formed on the ohmic electrode side high concentration semiconductor layer.
[0017]
According to the semiconductor device of the above embodiment, a diode having negative resistance in which an anode ohmic electrode and a cathode ohmic electrode are formed in a laminated structure having negative resistance diode characteristics formed by epitaxial growth on the semi-insulating substrate is provided. A first Schottky diode in which a Schottky electrode is formed on an active layer having a laminated structure having the negative resistance diode characteristic is provided in a region other than the formation region of the diode having the negative resistance. Furthermore, the Schottky electrode side low-concentration semiconductor layer having a Schottky diode characteristic having a Schottky diode characteristic formed by the epitaxial growth in a region other than the formation region of the diode having the negative resistance and the formation region of the first Schottky diode, A second Schottky diode having a Schottky electrode and an ohmic electrode formed on the ohmic electrode side high concentration semiconductor layer is provided. Accordingly, since there is no need to perform ion implantation and high-temperature heat treatment, problems such as the epitaxial structure of the diode having negative resistance and the deterioration of contact resistance are eliminated. In the first Schottky diode, since the Schottky electrode is formed on the active layer having a negative resistance diode characteristic, a Schottky diode having a large capacitance change suitable for use in a varactor diode or the like is obtained. In addition, in the second Schottky diode, a Schottky electrode is formed on the Schottky electrode side low concentration semiconductor layer and an ohmic electrode is formed on the ohmic electrode side high concentration semiconductor layer. A Schottky diode having a small resistance component and a small capacitance can be obtained. Such a first Schottky diode having a large capacitance change, a second Schottky diode having a small resistance component and a small capacitance, and a diode having a negative resistance can be integrated on the same substrate, thereby reducing signal loss. Miniaturization can be achieved.
[0018]
In one embodiment, the semiconductor device of the first invention is characterized in that an etching stop layer is stacked on the Schottky electrode side low concentration semiconductor layer.
[0019]
According to the semiconductor device of the above embodiment, by stacking the etching stop layer on the low-concentration semiconductor layer on the Schottky electrode side, the stacked structure having the diode characteristics having the negative resistance is selectively etched and removed. And the over-etching of the low-concentration semiconductor layer on the Schottky electrode side of the second Schottky diode is eliminated, and the thickness of the low-concentration semiconductor layer on the Schottky electrode side is controlled within the wafer surface by the thickness during epitaxial growth And variations among wafers can be reduced. Thereby, the reproducibility of the characteristics of the second Schottky diode is obtained.
[0020]
In one embodiment, the semiconductor device of the second invention is characterized in that an etching stop layer is laminated under the Schottky electrode side low concentration semiconductor layer.
[0021]
According to the semiconductor device of the embodiment, the Schottky electrode side low concentration semiconductor layer is selected by stacking the etching stop layer under the Schottky electrode side low concentration semiconductor layer of the stacked structure having the Schottky diode characteristics. Therefore, the multilayer structure having the negative resistance diode characteristics is not over-etched, and the active layer of the multilayer structure having the negative resistance diode characteristics is in-plane with the thickness during epitaxial growth. And the variation between wafers can be reduced. Thereby, reproducibility of the characteristics of the diode having negative resistance can be obtained.
[0022]
In one embodiment, the diode having negative resistance is a Gunn diode.
[0023]
According to the semiconductor device of the above embodiment, since the diode having the negative resistance is a Gunn diode, it is possible to integrate an oscillation element with low phase noise and a Schottky diode on the same substrate.
[0024]
In one embodiment, at least two of the diode having negative resistance, the first Schottky diode, and the second Schottky diode are connected by a transmission line.
[0025]
According to the semiconductor device of the above embodiment, the transmission line connecting the devices can be shortened by fabricating the diode having negative resistance and the first and second Schottky diodes on the same substrate. It is very effective in reducing signal loss.
[0026]
The semiconductor device manufacturing method of the present invention is the method of manufacturing the semiconductor device of the first invention, wherein at least the ohmic electrode side high concentration semiconductor layer and the Schottky electrode side low concentration semiconductor are formed on the semi-insulating substrate. A step of forming a laminated structure having a Schottky diode characteristic in which layers are sequentially laminated by epitaxial growth, and at least a high-concentration semiconductor layer on the anode ohmic electrode side, an active layer, and a cathode ohmic electrode on the laminated structure having the Schottky diode characteristic; Forming a laminated structure having negative resistance diode characteristics in which high-concentration semiconductor layers are sequentially laminated, and negative resistance by selectively etching the laminated structure having negative resistance diode characteristics. Diode region and first Schottky diode region And a second Schottky diode region by selectively etching the stacked structure having the Schottky diode characteristic in a region other than the diode region having the negative resistance and the first Schottky diode region. Forming a diode region having a negative resistance, a separation region separating the first Schottky diode region and the second Schottky diode region, and a diode region having the negative resistance. Forming an anode ohmic electrode and a cathode ohmic electrode, forming an ohmic electrode in the first and second Schottky diode regions, and forming a Schottky electrode in the first and second Schottky diode regions; Dies with negative resistance The anode ohmic electrode and the cathode ohmic electrode in the cathode region are connected to at least two of the ohmic electrode and the Schottky electrode in the first Schottky diode region and the ohmic electrode and the Schottky electrode in the second Schottky diode region. And a step of forming a transmission line.
[0027]
According to the semiconductor device manufacturing method, since there is no need to perform ion implantation and high-temperature heat treatment, problems such as an epitaxial structure of a diode having negative resistance and deterioration of contact resistance are eliminated. In the first Schottky diode, since the Schottky electrode is formed on the active layer having a negative resistance diode characteristic, a Schottky diode having a large capacitance change suitable for use in a varactor diode or the like is obtained. In addition, in the second Schottky diode, a Schottky electrode is formed on the Schottky electrode side low concentration semiconductor layer and an ohmic electrode is formed on the ohmic electrode side high concentration semiconductor layer. A Schottky diode having a small resistance component and a small capacitance can be obtained. Such a first Schottky diode having a large capacitance change, a second Schottky diode having a small resistance component and a small capacitance, and a diode having a negative resistance can be integrated on the same substrate, thereby reducing signal loss. Miniaturization can be achieved. In addition, a semiconductor device having a small in-plane variation in characteristics of the negative resistance diode and the first and second Schottky diodes can be easily manufactured on the same substrate.
[0028]
The semiconductor device manufacturing method according to the present invention is the method for manufacturing the semiconductor device according to the second invention, wherein at least the anode ohmic electrode side high-concentration semiconductor layer, the active layer, and the cathode ohmic electrode are formed on the semi-insulating substrate. Forming a laminated structure having a negative resistance diode characteristic in which a high-concentration semiconductor layer is sequentially laminated, and at least an ohmic electrode-side high-concentration semiconductor layer and a shot on the laminated structure having the negative resistance diode characteristic. A step of forming a stacked structure having a Schottky diode characteristic in which key-electrode-side low-concentration semiconductor layers are sequentially stacked by epitaxial growth, and a second Schottky diode by selectively etching the stacked structure having the Schottky diode characteristic. Forming the region, and the negative resistance diode Forming a diode region having a negative resistance and a first Schottky diode region by selectively etching a laminated structure having a diode characteristic; and the diode region having a negative resistance and the first Schottky Forming a separation region for separating the diode region and the second Schottky diode region; forming an anode ohmic electrode and a cathode ohmic electrode in the diode region having a negative resistance; and the first and second Schottky electrodes Forming an ohmic electrode in the diode region; forming a Schottky electrode in the first and second Schottky diode regions; an anode ohmic electrode in the diode region having negative resistance; a cathode ohmic electrode; 1 Schottky diode area Mikku electrode, is characterized by a step of forming a transmission line connecting at least two of the Schottky electrode and the second Schottky diode region ohmic electrode, the Schottky electrode.
[0029]
According to the semiconductor device manufacturing method, since there is no need to perform ion implantation and high-temperature heat treatment, problems such as an epitaxial structure of a diode having negative resistance and deterioration of contact resistance are eliminated. In the first Schottky diode, since the Schottky electrode is formed on the active layer having a negative resistance diode characteristic, a Schottky diode having a large capacitance change suitable for use in a varactor diode or the like is obtained. In addition, in the second Schottky diode, a Schottky electrode is formed on the Schottky electrode side low concentration semiconductor layer and an ohmic electrode is formed on the ohmic electrode side high concentration semiconductor layer. A Schottky diode having a small resistance component and a small capacitance can be obtained. Such a first Schottky diode having a large capacitance change, a second Schottky diode having a small resistance component and a small capacitance, and a diode having a negative resistance can be integrated on the same substrate, thereby reducing signal loss. Miniaturization can be achieved. In addition, a semiconductor device having a small in-plane variation in characteristics of the negative resistance diode and the first and second Schottky diodes can be easily manufactured on the same substrate.
[0030]
The millimeter-wave band communication apparatus of the present invention is a millimeter-wave band communication apparatus using the semiconductor device, wherein the diode having the negative resistance is used as an oscillation element, and the transmission line is used as an open stub or a short stub. The first Schottky diode is used as a varactor diode, and the second Schottky diode is used as a mixer.
[0031]
According to the millimeter-wave band communication apparatus having the above configuration, the diode having a negative resistance used as the oscillator, the transmission line used as an open stub or a short stub, the first Schottky diode used as a varactor diode, and the mixer are used. Since the second Schottky diode can be integrated on the same substrate, the transmission line is compared with a circuit in which a diode having a negative resistance, which is an oscillation element, and a Schottky diode are fabricated using different wafers and mounted. Loss and mounting loss (such as wire bond loss) can be reduced, and performance degradation such as deterioration of phase noise can be prevented.
[0032]
In one embodiment, the millimeter-wave band communication device is characterized in that the diode having the negative resistance is a Gunn diode.
[0033]
According to the millimeter-wave band communication device of the above embodiment, an oscillation element with small phase noise can be obtained by using a diode having negative resistance as a Gunn diode, and in particular, when used as an oscillation element of an oscillator, the performance of the oscillator Will improve.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a semiconductor device, a manufacturing method thereof, and a millimeter wave band communication device according to the present invention will be described in detail with reference to embodiments shown in the drawings.
[0035]
(First embodiment)
FIG. 1 is a cross-sectional view of a Gunn diode / Schottky diode integrated circuit of a semiconductor device according to a first embodiment of the present invention.
[0036]
In FIG. 1, a Gunn diode 11 as a diode having a negative resistance in a region A, a first Schottky diode 12 having a large capacitance change in a region B, a second Schottky diode 13 having a small resistance component and a small capacitance in a region C, a region Transmission lines 14 are respectively provided in D.
[0037]
In the region A, the cathode ohmic electrode 112 and the anode ohmic electrode 111 made of AuGe / Ni / Au are provided, and the Gunn diode 11 having the n-GaAs layer 107 serving as an active layer is formed. On the other hand, in the region B, the ohmic electrode 113 made of AuGe / Ni / Au, the n-GaAs layer 107 serving as an active layer, and the conductive film 116 made of Ti / Au on the n-GaAs layer 107 serving as the active layer. The first Schottky diode 12 having the Schottky characteristic formed by the above is configured. Further, in the region C, the second shot having the Schottky characteristic formed by the conductive film 116 made of Ti / Au on the ohmic electrode 114 made of AuGe / Ni / Au and the low concentration semiconductor layer 103 on the Schottky electrode side. A key diode 13 is configured. The periphery of the Gunn diode 11 and the first and second Schottky diodes 12 and 13 is etched to form an isolation region 130 that isolates the elements. In the region D, the transmission line 14 composed of the conductive film 116 and Au 117 is formed.
[0038]
Next, FIGS. 2 to 7 are cross-sectional views of steps for explaining a method of manufacturing the Gunn diode / Schottky diode integrated circuit.
[0039]
As shown in FIG. 2, an ohmic electrode side high-concentration semiconductor layer for a Schottky diode is formed on a semi-insulating GaAs substrate 101 by MBE (molecular beam epitaxial growth) method or MOCVD (metal organic chemical vapor deposition) method. n ⁺ -GaAs layer 102 (Si doping concentration 5 × 10 ¹⁸ cm ^-3 , Thickness 500 nm), n-GaAs layer 103 (Si doping concentration of 3 × 10 10) serving as a low concentration semiconductor layer on the Schottky electrode side ¹⁶ cm ^-3 , Thickness 300 nm), n-InGaP layer 104 (Si doping concentration 5 × 10 5) serving as an etching stopper layer ¹⁸ cm ^-3 , Thickness 20 nm), n serving as a high-concentration semiconductor layer on the anode ohmic electrode side for a Gunn diode ⁺ -GaAs layer 105 (Si doping concentration 5 × 10 ¹⁸ cm ^-3 , Thickness 500 nm), n-InGaP layer 106 (Si doping concentration of 3 × 10 10) serving as an etching stopper layer ¹⁸ cm ^-3 , Thickness 20 nm), n-GaAs layer 107 (Si doping concentration 2 × 10) to be an active layer ¹⁶ cm ^-3 , Thickness 2000 nm), n-Al serving as a cathode layer composed of a wide band gap layer _x Ga _1-x As layer 108 (X = 0.35, Si doping concentration 5 × 10 ¹⁷ cm ^-3 , Thickness 50nm), n-Al _x Ga _1-x As layer 109 (X = 0.35 → 0Si doping concentration 5 × 10 ¹⁷ cm ^-3 , Thickness 20 nm), n serving as the cathode ohmic electrode side high concentration semiconductor layer ⁺ -GaAs layer 110 (Si doping concentration 5 × 10 ¹⁸ cm ^-3 , Thickness 500 nm) is epitaxially grown sequentially.
[0040]
N above ⁺ The -GaAs layer 102 and the n-GaAs layer 103 constitute a stacked structure having Schottky diode characteristics. In addition, the above n ⁺ -GaAs layer 105, n-InGaP layer 106, n-GaAs layer 107, n-Al _x Ga _1-x As layer 108, n-Al _x Ga _1-x As layer 109 and n ⁺ The GaAs layer 110 constitutes a laminated structure having negative resistance diode characteristics.
[0041]
Thereafter, as shown in FIG. 3, the region that becomes the cathode of the Gunn diode is masked by the SiN film 119, and an etching solution containing sulfuric acid and hydrogen peroxide solution or an etching solution containing phosphoric acid and hydrogen peroxide solution is used. N until the n-GaAs layer 107 is exposed. ⁺ -GaAs layer 110, n-Al _x Ga _1-x As layer 109, n-Al _x Ga _1-x A predetermined region of the As layer 108 is removed by etching. Next, while leaving the SiN film mask 119, the Schottky electrode region for the Schottky diode in the region B is masked with the resist mask 120, and an etching solution containing sulfuric acid and hydrogen peroxide solution, phosphoric acid, hydrogen peroxide The n-GaAs layer 107 is removed by etching using an etching solution containing water. In the etching solution, the n-InGaP layer 106 is hardly etched. Next, the n-InGaP layer 106 is removed by etching using hydrochloric acid to form an n-type high-concentration semiconductor layer on the anode ohmic electrode side. ⁺ -The GaAs layer 105 is exposed. At this time, hydrochloric acid is removed by selectively etching only the n-InGaP layer 106.
[0042]
In this way, etching with a total film thickness of 2000 nm or more can be performed uniformly and accurately within the wafer surface. Further, by reusing the SiN film mask 119 without forming a new mask for the cathode region of the Gunn diode 11 when forming the Schottky electrode region forming mask, the n − of the Gunn diode 11 (shown in FIG. 1) is re-used. The side wall of the GaAs layer 107 can be etched smoothly without irregular steps. If there is an irregular step on the side wall of the n-GaAs layer 107, a frequency component unnecessary for the oscillation of the Gunn diode 11 is generated, resulting in a decrease in oscillation power and oscillation efficiency.
[0043]
Next, as shown in FIG. 4, a portion that becomes the Gunn diode 11 (shown in FIG. 1) in the region A and a portion that becomes the first Schottky diode 12 (shown in FIG. 1) in the region B are photoresist patterns or the like. After the masking with n, the n-InGaP layer 104 is exposed until the n-InGaP layer 104 is exposed as in the selective etching. ⁺ The GaAs layer 105 is selectively etched away. Subsequently, the n-InGaP layer 104 is selectively etched and removed until the n-GaAs layer 103 is exposed. At this time, by performing selective etching using the n-InGaP layer 104, the film thickness of the n-GaAs layer 103 is accurately controlled. Variation in the film thickness of the n-GaAs layer 103 results in variation in characteristics of the second Schottky diode 13 (shown in FIG. 1) in the region C.
[0044]
Next, a portion that becomes the Gunn diode 11 (shown in FIG. 1) in the region A, a portion that becomes the first Schottky diode 12 (shown in FIG. 1) in the region B, and a second Schottky diode 13 (shown in FIG. 1). The Schottky electrode region (shown in FIG. 1) is masked with a photoresist pattern or the like, and the n-GaAs layer 103 is removed by etching. ⁺ -Expose the GaAs layer 102; In the first embodiment, the n-GaAs layer 103 and n ⁺ An n-InGaP layer serving as an etching stopper layer is not provided between the -GaAs layer 102. This is because the n-GaAs layer 103 is not thick and n ⁺ This is because even if the GaAs layer 102 is slightly over-etched, an ohmic electrode having no problem can be formed for the second Schottky diode 13. In order to obtain a desired Schottky diode characteristic, when increasing the film thickness of the n-GaAs layer 103, it is desirable to provide an n-InGaP layer serving as an etching stopper layer.
[0045]
Next, as shown in FIG. 5, a portion that becomes the Gunn diode 11 (shown in FIG. 1) in the region A, a portion that becomes the first Schottky diode 12 (shown in FIG. 1) in the region B, and a region C After forming a resist mask by performing resist patterning so as to isolate the portion that becomes the second Schottky diode 13 (shown in FIG. 1), n ⁺ -The GaAs layer 102 is etched to mesa-separate. At this time, if separation by ion implantation is performed instead of mesa separation, the level difference becomes lower than that of mesa separation, and subsequent resist coating patterning becomes easy.
[0046]
Next, as shown in FIG. 6, the anode ohmic electrode formation region, the cathode ohmic electrode formation region of the Gunn diode 11 (shown in FIG. 1), and the first Schottky diode 12 (shown in FIG. 1) in the region B AuGe (100 nm) / Ni (15 nm) / Au (100 nm) is formed in the ohmic electrode forming region and the ohmic electrode forming region of the second Schottky diode 13 (shown in FIG. 1) in region C by vapor deposition or the like, The ohmic electrode is alloyed by heat treatment at 390 ° C. By doing so, the anode ohmic electrode 111, the cathode ohmic electrode 112, the ohmic electrode 113, and the ohmic electrode 114 are formed. Thereafter, a silicon nitride film (not shown) serving as a protective film is deposited to a thickness of 200 nm to improve reliability. Preferably, the refractive index of the silicon nitride film is 1.9 or more.
[0047]
Next, as shown in FIG. 7, the resist is left by resist patterning where the transmission line (wiring) of the step portion of each device (11, 12, 13 shown in FIG. 1) passes, and then the resist is softened at a temperature. A resist 115 that covers the stepped portion is formed by performing reflow by heat treatment. This resist 115 prevents the transmission line from being disconnected at the stepped portion.
[0048]
Next, as shown in FIG. 1, on the anode ohmic electrode 111 and the cathode ohmic electrode 112 of the Gunn diode 11, on the Schottky electrode formation region and the ohmic electrode 113 of the active layer nGaAs 107 of the first Schottky diode 12 in the region B, A contact hole (not shown) is formed on the Schottky electrode formation region of the Schottky electrode side low concentration semiconductor layer 103 in the region C and the ohmic electrode 114. Thereafter, a conductive film 116 made of Ti (100 nm) / Au (100 nm) is deposited on the entire surface by vapor deposition or the like. This conductive film 116 is used not only as a power supply metal for forming a subsequent transmission line (wiring) by plating but also as a Schottky electrode. The feed metal for forming the Schottky electrode and the transmission line 14 by plating is formed at the same time, but the Schottky electrode can also be formed after the ohmic electrode of the Schottky diode is formed. In this case, refractory metals such as Ti, W, and Mo, refractory nitrides, refractory silicides, and Al can be used as Schottky electrode materials, but a material that can form a stable Schottky barrier is selected. Is desirable.
[0049]
Next, a resist having a film thickness of 15 μm is applied, patterning of a region to be the transmission line 14 (116, 117) is performed, and then Au plating with a thickness of 9 μm is performed. Thereafter, the resist is removed, the unnecessary conductive film 116 is removed by etching, and the reflowed resist 115 is removed to form the transmission line 14 (shown in FIG. 1). In this first embodiment, a coplanar line is used as the transmission line 14, but a metal film is formed on the entire back surface of the semi-insulating GaAs substrate 101, and a microstrip line using the metal film as a ground conductor is used. Also good. Further, an NRD (non-radiative dielectric) guide may be used as a transmission line, and in particular, by using an NRD guide in the millimeter wave band, a transmission line with lower loss than a coplanar line or a microstrip line. It is possible to prevent performance degradation.
[0050]
Further, although Au plating is used to form the transmission line 14, Cu plating can also be used for cost reduction.
[0051]
In this first embodiment, wet etching is performed, but dry etching using a chlorine-based gas may be used instead. In the case of dry etching, since it is difficult to etch a layer containing In, the n-InGaP layer stops being etched in the same manner as in wet etching. In this embodiment, an n-type semiconductor is used for the low-concentration semiconductor layer on the Schottky electrode side of the second Schottky diode 13 in the region C. However, a p-type semiconductor may be used. In this case, the n-type semiconductor is used. Since a different Schottky electrode material can be used, the selection range at the time of process construction is expanded. Further, regarding the doping concentration of the low-concentration semiconductor layer on the Schottky electrode side of the second Schottky diode 13 in the region C, for example, when used for a mixer used in a 60 GHz band, the internal resistance is low with respect to the impedance of the Schottky diode. Specifically, the doping concentration is 2 × 10 ¹⁷ cm ^-3 The film thickness is preferably as follows, and the film thickness is preferably from 100 nm to 200 nm.
[0052]
In the first embodiment, the resist 115 reflowed so that the transmission line 14 at the step portion of each device (11, 12, 13) is not disconnected is used. Instead, polyimide, benzocyclobutene, spin-on glass, or the like is used. May be applied to form a planarizing film. For example, as shown in FIG. 8, a planarization film 118 is formed, a contact hole mask is formed on each electrode, the planarization film 118 is processed by dry etching to form a contact hole, and then wiring is performed from each electrode. The transmission line 14 may be formed on the planarizing film 118 by drawing out. In this case, since the contact hole mask is formed on the planarization film 118, photolithography with a size of 1 μm or less can be facilitated, a fine contact hole can be formed, and each device size can also be miniaturized.
[0053]
In the present invention, the GaAs / AlGaAs system is used, but other semiconductors that generate negative resistance may be used. For example, when an InP / InGaAs system is used, characteristics such as efficiency at a high frequency of the Gunn diode are improved as compared with a GaAs / AlGaAs system.
[0054]
The first Schottky diode 12 having a large capacitance change, the second Schottky diode 13 having a small resistance component and a small capacitance, and the Gunn diode 11 can be integrated on the same substrate, reducing the signal loss and reducing the size. Can be achieved.
[0055]
Further, the n-InGaP layer 104 serving as an etching stopper layer is laminated on the n-GaAs layer 103 serving as the low-concentration semiconductor layer on the Schottky electrode side, thereby selecting the laminated structure having the diode characteristics having the negative resistance. Therefore, the n-GaAs layer 103 which becomes the low-concentration semiconductor layer on the Schottky electrode side of the second Schottky diode 13 is not over-etched, and the thickness of the n-GaAs layer 103 is reduced. The thickness at the time of epitaxial growth can be kept as it is, and variations between wafers can be reduced. Therefore, the characteristics of the second Schottky diode 13 with good reproducibility can be obtained.
[0056]
Further, since the diode having the negative resistance is the Gunn diode 11, the oscillation element having a small phase noise and the first and second Schottky diodes 12 and 13 can be integrated on the same substrate.
[0057]
Also, by fabricating the Gunn diode 11 and the first and second Schottky diodes 12 and 13 on the same substrate, the transmission line connecting the devices can be shortened, which is very effective in reducing signal loss. It is.
[0058]
(Second embodiment)
Generally speaking, epitaxial growth greatly affects the state of the lower layer. In the first embodiment, since the material of the Gunn diode 11 is laminated on the material of the Schottky diode 12, there are many InGaP layers and p-type GaAs that cause the crystal lattice to be distorted under the structure of the Gunn diode 11. become. In addition, since the active layer of the Gunn diode 11 has a low concentration and a large film thickness, epitaxial growth is difficult. Specifically, when the lattice of the active layer is distorted and defects increase, the carrier concentration decreases, making it difficult to obtain stable active layer characteristics. Such a change in the characteristics of the active layer greatly affects the oscillation frequency, efficiency, noise characteristics, and the like of the Gunn diode.
[0059]
Therefore, in the second embodiment of the present invention, a Gunn diode / Schottky diode integrated circuit in which the characteristics of the active layer of the Gunn diode are stabilized by stacking the Schottky diode structure on the Gunn diode structure will be described. .
[0060]
9, the Gunn diode 21 as a diode having a negative resistance in the region A, the first Schottky diode 22 having a large capacitance change in the region B, the second Schottky diode 23 having a small resistance component and a small capacitance in the region C, A transmission line 24 is provided in the region D.
[0061]
In the region A, the cathode ohmic electrode 212 and the anode ohmic electrode 211 made of AuGe / Ni / Au are provided, and the Gunn diode 21 having the n-GaAs layer 207 serving as an active layer is formed. On the other hand, in the region B, the first Schottky having the Schottky characteristic formed by the ohmic electrode 213 made of AuGe / Ni / Au, the n-GaAs layer 207 to be the active layer, and the conductive film 216 made of Ti / Au. A diode 22 is configured. Further, in the region C, the Schottky formed by the conductive film 216 made of Ti / Au on the ohmic electrode 214 made of AuGe / Ni / Au and the n-GaAs layer 221 serving as the low concentration semiconductor layer on the Schottky electrode side. A second Schottky diode 23 having characteristics is configured. The periphery of the Gunn diode 21 and the first and second Schottky diodes 22 and 23 is etched to form an isolation region 230 that isolates the elements. In the region D, a transmission line 24 composed of the conductive film 216 and Au 217 is formed.
[0062]
10 to 14 are cross-sectional views illustrating the steps of the method for manufacturing the Gunn diode / Schottky diode integrated circuit.
[0063]
As shown in FIG. 10, an anode ohmic electrode side high-concentration semiconductor layer for a Gunn diode is formed on a semi-insulating GaAs substrate 201 by MBE (molecular beam epitaxy) method or MOCVD (metal organic vapor phase epitaxy) method. n ⁺ -GaAs layer 205 (Si doping concentration 5 × 10 ¹⁸ cm ^-3 , Thickness 500 nm), n-InGaP layer 206 (Si doping concentration 3 × 10 5) serving as an etching stopper layer ¹⁸ cm ^-3 , Thickness 20 nm), n-GaAs layer 207 (Si doping concentration 2 × 10) serving as an active layer ¹⁶ cm ^-3 , Thickness 2000 nm), n-Al serving as a cathode layer composed of a wide band gap layer _x Ga _1-x As layer 208 (X = 0.35, Si doping concentration 5 × 10 ¹⁷ cm ^-3 , Thickness 50nm), n-Al _x Ga _1-x As layer 209 (X = 0.35 → 0, Si doping concentration 5 × 10 ¹⁷ cm ^-3 , Thickness 20 nm) to be a cathode ohmic electrode side high concentration semiconductor layer (and an ohmic electrode side high concentration semiconductor layer for the second Schottky diode 23) ⁺ -GaAs layer 210 (Si doping concentration 5 × 10 ¹⁸ cm ^-3 , Thickness 500 nm), n-InGaP layer 204 (Si doping concentration 5 × 10 5) serving as an etching stopper layer ¹⁸ cm ^-3 , Thickness 20 nm), an n-GaAs layer 221 (Si doping concentration of 1 × 10 10) serving as a low concentration semiconductor layer on the Schottky electrode side ¹⁷ cm ^-3 , Thickness of 150 nm) is sequentially epitaxially grown.
[0064]
Thereafter, as shown in FIG. 11, the region to be the second Schottky diode 22 is masked with a photoresist pattern or the like, and the n-GaAs layer 221 is selectively etched and removed until the n-InGaP layer 204 is exposed. . Next, the n-InGaP layer 204 is removed by etching using hydrochloric acid to form a high-concentration semiconductor layer on the cathode ohmic electrode side. ⁺ -Expose the GaAs layer 210; At this time, the n-InGaP layer 204 is used as an etching stopper layer, but an AlGaAs layer may be used as the etching stopper layer.
[0065]
Next, the cathode region of the Gunn diode 21 (shown in FIG. 9) and the region of the second Schottky diode 22 (shown in FIG. 9) are masked with the SiN film 219, and n until the n-GaAs layer 207 is exposed. ⁺ -GaAs layer 210, n-Al _x Ga _1-x As layer 209 and n-Al _x Ga _1-x The As layer 208 is removed by etching. Next, while leaving the SiN film mask 219, the Schottky electrode region for the second Schottky diode 23 (shown in FIG. 9) in the region B is masked with the resist mask 220, and the n-GaAs layer 207 is etched. Remove. Subsequently, the n-InGaP layer 206 is selectively etched and removed. ⁺ -The GaAs layer 205 is exposed.
[0066]
Next, as shown in FIG. 12, the portion of the Gunn diode 21 (shown in FIG. 9) in the region A, the portion of the first Schottky diode 22 (shown in FIG. 9) in the region B, and the second of the region C A resist mask (not shown) is formed by performing resist patterning so as to isolate the portion of the Schottky diode 23 (shown in FIG. 9), and n ⁺ -The GaAs layer 205 is etched to mesa-separate.
[0067]
Next, as shown in FIG. 13, the anode ohmic electrode formation region and the cathode ohmic electrode formation region of the Gunn diode 21 in the region A, the ohmic electrode formation region of the first Schottky diode 22 in the region B, and the region C AuGe (100 nm) / Ni (15 nm) / Au (100 nm) is formed in the ohmic electrode formation region of the two Schottky diode 23 by vapor deposition or the like, and the ohmic electrode is alloyed by heat treatment at 390 ° C. By doing so, the anode ohmic electrode 211, the cathode ohmic electrode 212, the ohmic electrode 213, and the ohmic electrode 214 are formed. Thereafter, a silicon nitride film (not shown) serving as a protective film is deposited to a thickness of 200 nm.
[0068]
Next, as shown in FIG. 14, the resist is left by resist patterning at the place where the transmission line (wiring) of the stepped portion of each device (21, 22, 23 shown in FIG. 9) passes, and then the temperature at which the resist softens Then, heat treatment is performed and reflow is performed to form a resist 215 that covers the stepped portion. The resist 215 prevents the transmission line from being disconnected at the stepped portion.
[0069]
Next, as shown in FIG. 9, the Schottky of the n-GaAs layer 207 serving as the active layer of the first Schottky diode 22 in the region B on the anode ohmic electrode 211 and the cathode ohmic electrode 212 of the Gunn diode 21 in the region A. Contact holes (on the electrode formation region and the ohmic electrode 213, and on the ohmic electrode 214 of the second Schottky diode 23 in the region C and the Schottky electrode formation region on the n-GaAs layer 221 serving as the Schottky electrode side low concentration semiconductor layer) (Not shown). Thereafter, a conductive film 216 made of Ti (100 nm) / Au (100 nm) is deposited on the entire surface of the substrate by vapor deposition or the like. The conductive film 216 is used not only as a power supply metal for forming the subsequent transmission line 24 (wiring) by plating but also as a Schottky electrode. At this time, the feed metal for forming the Schottky electrode and the transmission line 24 by plating is formed at the same time. However, the Schottky electrode can also be formed after the ohmic electrode of the Schottky diode is formed. In this case, refractory metals such as Ti, W, and Mo, refractory nitrides, refractory silicides, and Al can be used as Schottky electrode materials, but a material that can form a stable Schottky barrier is selected. Is desirable.
[0070]
Next, a resist having a film thickness of 15 μm is applied, patterning of a region to be the transmission line 24 is performed, and then Au plating with a thickness of 9 μm is performed. Thereafter, the resist is removed and the unnecessary conductive film 216 is etched and removed, and the reflowed resist 214 is removed to form the transmission line 24.
[0071]
The first Schottky diode 22 having a large capacitance change, the second Schottky diode 23 having a small resistance component and a small capacitance, and the Gunn diode 21 can be integrated on the same substrate, reducing the signal loss and reducing the size. Can be achieved.
[0072]
Further, by stacking an n-InGaP layer 204 serving as an etching stopper layer under the n-GaAs layer 221 serving as a Schottky electrode side low concentration semiconductor layer, an n-GaAs layer 221 serving as a Schottky electrode side low concentration semiconductor layer. N-GaAs layer that becomes an active layer of the multilayer structure having the negative resistance diode characteristic without over-etching the multilayer structure having the negative resistance diode characteristic. 207 can be kept at the thickness during epitaxial growth, and variation between wafers can be reduced. As a result, the characteristics of a diode having a negative resistance with good reproducibility can be obtained.
[0073]
Further, since the diode having the negative resistance is the Gunn diode 21, the oscillation element with small phase noise and the first and second Schottky diodes 22 and 23 can be integrated on the same substrate.
[0074]
Also, by fabricating the Gunn diode 21 and the first and second Schottky diodes 22 and 23 on the same substrate, the transmission line connecting the devices can be shortened, which is very effective in reducing signal loss. It is.
[0075]
(Third embodiment)
FIG. 15 is a diagram showing a corresponding circuit of a voltage controlled oscillator using the semiconductor device of the third embodiment of the present invention. A Gunn diode and a Schottky diode manufactured on the same substrate in the semiconductor devices of the first and second embodiments are used for this voltage controlled oscillator (hereinafter referred to as VCO).
[0076]
In the VCO, an oscillation element 601 using a Gunn diode (region A in FIG. 1 or FIG. 9), a varactor diode 602 using a second Schottky diode (region B in FIG. 1 or FIG. 9), and a transmission line A λ / 4 long stub 604 using the resonator (region D in FIG. 1 or FIG. 9) as a resonator and a λ / 4 long stub 603 using the transmission line (region D in FIGS. 1 and 9) as a ground. ing. One end of the oscillation element 601 is connected to the ground, and the other end of the oscillation element 601 is connected to a Gunn diode bias circuit (not shown). The other end of the oscillation element 601 is connected to one end of a λ / 4 long stub 604, and the other end of the λ / 4 long stub 604 is connected to one end of a varactor diode 602. A varactor bias circuit (not shown) is connected to the other end of the varactor diode 602 and one end of the λ / 4 long stub 603 is connected. RF (radio frequency) is output from the connection point between the oscillation element 601 and the λ / 4 long stub 604.
[0077]
In the millimeter wave band (30 GHz to 90 GHz), if a VCO is configured by fabricating and mounting Gunn diodes and Schottky diodes on different wafers, transmission line losses and losses during mounting (such as wire bond losses) will occur. This leads to a decrease in performance such as an increase in Q value and a decrease in phase noise. Therefore, producing a Gunn diode and a Schottky diode, which are oscillation elements, on the same substrate and shortening the transmission line between devices is very effective in reducing signal loss and miniaturization.
[0078]
At this time, the capacity of the varactor diode 602 can be changed by the device area of the first Schottky diode. For example, the Schottky junction capacitance of the first and second embodiments has a device area of 50 μm. ² In the unbiased state, it is about 30 fF, and the capacitance can be further reduced by extending the depletion layer by applying a bias. Therefore, since the capacity increases in proportion to the area when the area is increased, it can be flexibly handled by considering it at the time of design. The varactor diode 602 can select a capacitance value used in a necessary frequency band by changing the impurity concentration and film thickness of the n-GaAs layer.
[0079]
Furthermore, when it is necessary to increase the Q value of the VCO, it is effective to provide a dielectric resonator on the substrate. However, since the VCO is conventionally configured as a hybrid type, the dielectric resonator manufactured separately is used. Was implemented. In such a method, there is a problem that if the accuracy at the time of mounting the dielectric resonator is poor, the coupling of the electromagnetic field is deteriorated and a sufficient effect cannot be obtained. Particularly in the millimeter wave band, since the wavelength is short, high accuracy is required. On the other hand, in the third embodiment, since the wafer is monolithic, dielectric resonators can be formed on each chip simultaneously with high accuracy, and variations in characteristics between the chips are reduced. Specifically, after the transmission line is formed, the dielectric is deposited by sputtering, vapor deposition, or the like, or a sol / gel-like dielectric is spin coated to form the entire surface of the wafer. Thereafter, a dielectric resonator can be manufactured by forming an etching mask using photolithography using a resist or the like and etching away unnecessary dielectrics. Since the manufacturing accuracy of the etching mask by photolithography can be 1 μm or less, the distance between the dielectric resonator and the transmission line can be controlled with high accuracy.
[0080]
Further, according to the VCO of the third embodiment, in addition to loss reduction and downsizing, there is an advantage that the oscillation frequency is stabilized when mounted on the package. Details will be described with reference to FIG. FIG. 16A shows an example in which the VCO chip 911 of this embodiment is mounted on a certain package. This package includes an alumina member 912 having a recess laminated on a metal ground 910, an alumina member 913 forming a side wall, and a lid 915. A VCO chip 911 is accommodated in the concave portion of the alumina member 912, and a transmission line (not shown) of the VCO chip 911 and a transmission line (not shown) formed on the upper surface of the alumina member 912 are connected by an Au wire 914. ing. On the other hand, FIG. 16B shows a conventional example in which a Gunn diode 916 and a Schottky diode 917 are mounted as separate chips in the same type of package. In this conventional example, the Gunn diode 916 is housed in the recess of the alumina member 912, but the Schottky diode 917 is mounted on the upper surface of the alumina member 912. Therefore, the alumina member 913B in FIG. 16B is higher than that in FIG. As described above, in the mounting form of FIG. 16A, since it is not necessary to mount a chip-like element on the upper surface of the alumina member 912, the height h of the alumina member 913 of the package can be lowered accordingly. .
[0081]
This difference in the height of the package results in a difference in the stray capacitance in the package. If the stray capacitance is large, unnecessary oscillation occurs in the package or the oscillation of the VCO stops. Therefore, it is very important to keep the height h of the package low. In particular, in a VCO in the millimeter wave band, since the oscillation frequency is high, there is a tendency that oscillation lower than a necessary oscillation frequency is likely to occur. Therefore, it can be said that the VCO using the mounting form of FIG. 16A is suitable for the millimeter wave band.
[0082]
FIG. 17A is a configuration diagram of a transmitter as a millimeter wave band communication device using the VCO, and FIG. 17B is a configuration of a receiver as a millimeter wave band communication device using the VCO. FIG.
[0083]
The transmitter illustrated in FIG. 17A includes a mixer 902, a filter 903, a power amplifier 904, and an antenna 905 in addition to the oscillator 901. The output terminal of the oscillator 901 is connected to the input terminal of the mixer 902, and one end of the filter 903 is connected to the output terminal of the mixer 902. An input of a power amplifier 904 is connected to the other end of the filter 903, and an antenna 905 is connected to an output terminal of the power amplifier 904.
[0084]
In addition to the oscillator 901, the receiver illustrated in FIG. 17B includes a mixer 902, a filter 903, a low noise amplifier 906, and an antenna 905. The input terminal of the low noise amplifier 906 is connected to the antenna 905, and one end of the filter 903 is connected to the output terminal of the low noise amplifier 906. One input terminal of the mixer 902 is connected to the other end of the filter 903, and the output terminal of the oscillator 901 is connected to the other input terminal of the mixer 902.
[0085]
The VCO configured in the third embodiment is used for the transmitter and the receiver, the VCO of FIG. 15 is used for the oscillator 901, the transmission line (area D of FIG. 1 or FIG. 9) is used for the filter 903, and the mixer A second Schottky diode (region B in FIG. 1 or FIG. 9) is used at 902. In order to obtain good characteristics with the mixer 902, a second Schottky diode with a small resistance and a small capacity is required. However, as in the first and second embodiments, it is dedicated to the upper or lower layer of the Gunn diode epitaxial structure. This layer can be easily manufactured. If the active layer of the Gunn diode is used, it is necessary to make the active layer thin by etching, which makes it difficult to control and a second Schottky diode with a large capacitance change can be obtained. It will disappear.
[0086]
Thus, since the transmitter and the receiver can easily produce Schottky diodes having different characteristics, circuits having an oscillator function and a mixer function can be integrated on the same substrate. The power amplifier 904 and the low noise amplifier 906 need to be separately mounted with transistors. However, if the local signal from the oscillator 901 is sufficiently large, the power amplifier 904 and the low noise amplifier 906 are not necessary, and transmission in the millimeter wave band is required. And receiver can be monolithic. Further, in the millimeter wave band, when the loss of the transmission line between the oscillator 901 and the mixer 902 is large, the problem that the mixer 902 cannot be operated with a large signal is similarly applied to the gun that is an oscillation element. The Schottky diode that constitutes the diode and the mixer is manufactured on the same substrate, and the transmission line between the devices is shortened, which is very effective in reducing the signal loss.
[0087]
In the first to third embodiments, the Gunn diode is used as the negative resistance diode, but a negative resistance diode such as a tunnel diode or an impat diode may be used.
[0088]
【The invention's effect】
As is clear from the above, according to the semiconductor device and the manufacturing method thereof of the present invention, without using a complicated process, a diode having a negative resistance, which is an oscillation element with high frequency power and low phase noise, and capacitance change The first Schottky diode having a large resistance and the second Schottky diode having a small resistance component and a small capacitance can be easily integrated on the same substrate.
[0089]
Further, according to the millimeter wave band communication device of the present invention, signal loss can be reduced and the size can be reduced, and a high performance millimeter wave band communication device can be realized.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a Gunn diode / Schottky diode integrated circuit as a semiconductor device according to a first embodiment of the present invention;
FIG. 2 is a cross-sectional view for explaining one step of the manufacturing process of the semiconductor device.
FIG. 3 is a cross-sectional view for explaining one step of the manufacturing process of the semiconductor device following FIG. 2;
FIG. 4 is a cross-sectional view for explaining one step of the manufacturing process of the semiconductor device following FIG. 3;
FIG. 5 is a cross-sectional view for explaining one step of the manufacturing process of the semiconductor device following FIG. 4;
FIG. 6 is a cross-sectional view for explaining one step of the manufacturing process of the semiconductor device subsequent to FIG.
FIG. 7 is a cross-sectional view for explaining one step of the manufacturing process of the semiconductor device following FIG. 6;
FIG. 8 is a cross-sectional view for explaining one step of the manufacturing process of the semiconductor device following FIG.
FIG. 8 is a cross-sectional view of a Gunn diode / Schottky diode integrated circuit as a semiconductor device according to a second embodiment of the present invention;
FIG. 10 is a cross-sectional view for explaining a step in the manufacturing process of the semiconductor device.
FIG. 11 is a cross-sectional view for explaining one step of the manufacturing process of the semiconductor device following FIG. 10;
12 is a cross-sectional view for explaining one step of the manufacturing process of the semiconductor device following FIG. 11. FIG.
FIG. 13 is a cross-sectional view for explaining one step of the manufacturing process of the semiconductor device following FIG. 12;
FIG. 14 is a cross-sectional view for explaining one step of the manufacturing process of the semiconductor device following FIG. 13;
FIG. 15 is a diagram showing an equivalent circuit of a VCO using a semiconductor device according to a third embodiment of the present invention.
16A is a cross-sectional view in which the VCO is mounted on a package, and FIG. 16B is a cross-sectional view in which the VCO is mounted on the package in a hybrid configuration.
FIG. 17A is a configuration diagram of a transmitter using the VCO, and FIG. 17B is a configuration diagram of a receiver using the VCO.
FIG. 18 is a cross-sectional view illustrating a conventional semiconductor device.
[Explanation of symbols]
11, 21 ... Gunn diode,
12, 22 ... first Schottky diode,
13, 23 ... second Schottky diode,
14, 24 ... transmission line,
101 ... Semi-insulating GaAs substrate,
102 ... n ⁺ -GaAs layer,
103 ... n-GaAs layer,
104: n-InGaP layer,
105 ... n ⁺ -GaAs layer,
106: n-InGaP layer,
107: n-GaAs layer,
108 ... n-Al _x Ga _1-x As layer,
109 ... n-Al _x Ga _1-x As layer,
110 ... n ⁺ -GaAs layer,
111 ... Anode ohmic electrode,
112 ... Cathode ohmic electrode,
113 ... Ohmic electrode,
114: Ohmic electrode,
115 ... resist,
116 ... conductive film,
117 ... transmission line,
118 ... planarization film,
119 ... SiN film,
120 ... resist mask,
121 ... n-GaAs layer,
130 ... separation region,
201: Semi-insulating GaAs substrate,
204: n-InGaP layer,
205 ... n ⁺ -GaAs layer,
206 ... n-InGaP layer,
207 ... n-GaAs layer,
208 ... n-Al _x Ga _1-x As layer,
209 ... n-Al _x Ga _1-x As layer,
210 ... n ⁺ -GaAs layer,
211 ... Anode ohmic electrode,
212 ... Cathode ohmic electrode,
213 ... Ohmic electrode,
214 ... Ohmic electrode,
215 ... resist,
216 ... conductive film,
217 ... Au,
221 ... n-GaAs layer,
230 ... separation region,
601 ... an oscillation element,
602: Varactor diode,
603 ... λ / 4 long stub,
604 ... λ / 4 long stub,
801: Semi-insulating GaAs substrate,
802 ... n ⁺ -GaAs layer,
803 ... n-GaAs layer,
804 ... p-GaAs layer,
805 ... p ⁺ -GaAs layer,
806 ... TiW,
807 ... Au,
808 ... Ti,
809 ... Au,
810 ... Ti,
811 ... Au,
901 ... an oscillator,
902 ... Mixer,
903 ... filter,
904 ... Power amplifier,
905 ... an antenna,
906: Low noise amplifier,
910 ... Metal ground,
911 ... VCO,
912, 913, 913B ... alumina member,
914 ... Au wire,
915 ... lid,
916 ... Gunn diode,
917: Schottky diode.

Claims (10)

A laminated structure having a Schottky diode characteristic formed by epitaxial growth on a semi-insulating substrate and at least an ohmic electrode side high concentration semiconductor layer and a Schottky electrode side low concentration semiconductor layer are sequentially laminated,
A semiconductor device comprising a laminated structure having a negative resistance diode characteristic formed by epitaxial growth on the laminated structure having the Schottky diode characteristic,
Provided in a layered structure having the above negative resistance diode characteristics, provided in a region other than the formation region of the negative resistance diode in which the anode ohmic electrode and the cathode ohmic electrode are formed, and the diode having the negative resistance, A first Schottky diode in which a Schottky electrode is formed on an active layer having a multilayer structure having the negative resistance diode characteristics;
A Schottky is provided on the low-concentration semiconductor layer on the Schottky electrode side of the stacked structure provided in a region other than the formation region of the diode having the negative resistance and the formation region of the first Schottky diode. A semiconductor device comprising: a second Schottky diode in which an electrode is formed and an ohmic electrode is formed on the ohmic electrode side high concentration semiconductor layer. A laminated structure having negative resistance diode characteristics formed by epitaxial growth on a semi-insulating substrate;
A multilayer structure having a Schottky diode characteristic formed by epitaxial growth on the multilayer structure having the negative resistance diode characteristic and having at least an ohmic electrode side high concentration semiconductor layer and a Schottky electrode side low concentration semiconductor layer sequentially stacked. A semiconductor device,
Provided in a layered structure having the above negative resistance diode characteristics, provided in a region other than the formation region of the negative resistance diode in which the anode ohmic electrode and the cathode ohmic electrode are formed, and the diode having the negative resistance, A first Schottky diode in which a Schottky electrode is formed on an active layer having a multilayer structure having the negative resistance diode characteristics;
A Schottky is provided on the low-concentration semiconductor layer on the Schottky electrode side of the stacked structure provided in a region other than the formation region of the diode having the negative resistance and the formation region of the first Schottky diode. A semiconductor device comprising: a second Schottky diode in which an electrode is formed and an ohmic electrode is formed on the ohmic electrode side high concentration semiconductor layer. The semiconductor device according to claim 1,
An etching stop layer is stacked on the Schottky electrode side low concentration semiconductor layer. The semiconductor device according to claim 2,
An etching stop layer is laminated below the Schottky electrode side low concentration semiconductor layer. 5. The semiconductor device according to claim 1, wherein:
A semiconductor device, wherein the diode having negative resistance is a Gunn diode. The semiconductor device according to claim 1 or 2,
A semiconductor device, wherein at least two of the diode having negative resistance, the first Schottky diode, and the second Schottky diode are connected by a transmission line. A method of manufacturing a semiconductor device according to claim 1,
Forming a laminated structure having a Schottky diode characteristic, in which at least an ohmic electrode side high concentration semiconductor layer and a Schottky electrode side low concentration semiconductor layer are sequentially laminated on a semi-insulating substrate by epitaxial growth;
A layered structure having a negative resistance diode characteristic in which at least an anode ohmic electrode side high-concentration semiconductor layer, an active layer, and a cathode ohmic electrode side high-concentration semiconductor layer are sequentially laminated on the layered structure having the Schottky diode characteristic is epitaxially grown. Forming, and
Forming a diode region having a negative resistance and a first Schottky diode region by selectively etching the laminated structure having the negative resistance diode characteristics;
Forming a second Schottky diode region by selectively etching the stacked structure having the Schottky diode characteristics in a region other than the diode region having the negative resistance and the first Schottky diode region;
Forming an isolation region that isolates the diode region having the negative resistance and the first Schottky diode region and the second Schottky diode region;
Forming an anode ohmic electrode and a cathode ohmic electrode in the diode region having negative resistance, and forming an ohmic electrode in the first and second Schottky diode regions;
Forming a Schottky electrode in the first and second Schottky diode regions;
At least one of an anode ohmic electrode, a cathode ohmic electrode in the diode region having negative resistance, an ohmic electrode in the first Schottky diode region, a Schottky electrode, an ohmic electrode in the second Schottky diode region, and a Schottky electrode Forming a transmission line connecting the two, a method of manufacturing a semiconductor device. A method of manufacturing a semiconductor device according to claim 2,
Forming a laminated structure having a negative resistance diode characteristic by epitaxial growth on a semi-insulating substrate, in which at least an anode ohmic electrode side high concentration semiconductor layer, an active layer, and a cathode ohmic electrode side high concentration semiconductor layer are sequentially laminated; Forming a laminated structure having a Schottky diode characteristic by epitaxially growing at least an ohmic electrode side high-concentration semiconductor layer and a Schottky electrode side low-concentration semiconductor layer on the laminated structure having the negative resistance diode characteristic; and ,
Forming a second Schottky diode region by selectively etching the stacked structure having the Schottky diode characteristics;
Forming the diode region having the negative resistance and the first Schottky diode region by selectively etching the laminated structure having the negative resistance diode characteristics;
Forming an isolation region that isolates the diode region having the negative resistance and the first Schottky diode region and the second Schottky diode region;
Forming an anode ohmic electrode and a cathode ohmic electrode in the diode region having negative resistance, and forming an ohmic electrode in the first and second Schottky diode regions;
Forming a Schottky electrode in the first and second Schottky diode regions;
At least one of an anode ohmic electrode, a cathode ohmic electrode in the diode region having negative resistance, an ohmic electrode in the first Schottky diode region, a Schottky electrode, an ohmic electrode in the second Schottky diode region, and a Schottky electrode Forming a transmission line connecting the two, a method of manufacturing a semiconductor device. A millimeter-wave band communication device using the semiconductor device according to claim 6,
Using the diode having the negative resistance as an oscillation element,
Use the transmission line as an open stub or short stub,
Using the first Schottky diode as a varactor diode,
A millimeter-wave band communication apparatus using the second Schottky diode as a mixer. In the millimeter waveband communication device according to claim 9,
A millimeter-wave band communication device, wherein the diode having negative resistance is a Gunn diode.

Images