JPH0618272B2 - Shutter-barrier barrier semiconductor device - Google Patents

Description

The present invention relates to a high breakdown voltage shutter barrier semiconductor device.

[Problems to be Solved by Conventional Techniques and Inventions]

The shutter barrier diode is widely used in a high-frequency rectifier circuit and the like by taking advantage of good high-speed response (high-speed switching characteristic) and low loss. But,
The breakdown voltage of the shutter barrier barrier diode (the breakdown voltage around the shutter barrier) is significantly lower than the bulk breakdown voltage (the breakdown voltage at the center of the shutter barrier).
There is a problem that it is difficult to increase the breakdown voltage.

Providing a field plate or a guard ring in order to solve this problem is known, for example, in the second edition of "Fixix of Semiconductor Devices" by S.M.J.E., USA. Also,
The use of both field plates and guard rings has already been done.

A shutter plate diode having a field plate structure is an n ^{+ type} semiconductor region, an n type semiconductor region formed on the n ^{+ type} semiconductor region, and a metal electrode capable of forming a shutter type barrier formed on the n ^{+ type} semiconductor region (hereinafter referred to as a barrier metal). An electrode or a barrier electrode), an insulating layer formed on the n-type semiconductor region so as to surround the barrier metal electrode, a field plate provided on the insulating layer and connected to the barrier metal electrode, n ^And an ohmic electrode connected to the ^{+ type} semiconductor region. When a reverse voltage is applied between the barrier metal electrode and the ohmic electrode, a depletion layer is generated between the barrier metal electrode and the n-type semiconductor region, and the field effect of the field plate is also exerted on the n-type semiconductor region below the field plate. As a result, a depletion layer is generated and the concentration of the electric field on the periphery of the barrier metal electrode is mitigated, and the peripheral breakdown voltage of the shutter barrier is improved. However, it was practically difficult to satisfactorily reduce the concentration of the electric field and significantly improve the breakdown voltage.

On the other hand, the Schottky barrier diode having a guard ring structure has a guard ring composed of ap ^{+ type} semiconductor region which is connected to the periphery of the barrier metal electrode when viewed in plan and is arranged so as to surround the barrier metal electrode. The p ^{+ -type} semiconductor region of the guard ring forms a pn junction with the n-type semiconductor region, and when a reverse voltage is applied to this pn junction, the depletion layer spreads more effectively than around the shutter barrier. As a result, the peripheral breakdown voltage of the barrier metal electrode can be improved. However, since the structure is such that the Schottky barrier diode and the pn junction diode are arranged in parallel, when a forward voltage is applied and a forward current flows, a small number of carriers are injected at the pn junction portion, and High-speed response, which is one of the features, is reduced. Further, although a combined structure of a guard ring and a field plate is also widely used, it is difficult to significantly increase the withstand voltage.

In order to solve the above problems, it is known to form a resistance layer having a taper and a Schottky barrier effect around the Schottky barrier electrode.
No. 63 publication. According to this method, it is possible to increase the breakdown voltage.

However, it is difficult to form a resistance layer having a taper. Further, the above patent publication does not disclose a technique for reducing the reverse current due to the breakdown at the outer peripheral edge of the resistance layer.

Therefore, an object of the present invention is to provide a Schottky barrier semiconductor device that can easily achieve improvement in breakdown voltage and can reduce reverse current due to breakdown at the outer peripheral edge of the resistance layer.

[Means for Solving the Problems] The present invention for achieving the above object is directed to a barrier formed on a semiconductor region so that a Schottky barrier can be generated between the semiconductor region and the semiconductor region. Between the electrode and the semiconductor region, the electrode being disposed on the semiconductor region so as to surround the barrier electrode, electrically connected to the barrier electrode, and having a sheet resistance larger than that of the barrier electrode; A first thin layer formed to produce a Schottky barrier at
A second layer disposed on the first thin layer, having a sheet resistance larger than the barrier electrode but smaller than the first thin layer, and electrically connected to the barrier electrode;
And a distance from the barrier electrode to the outer peripheral edge of the second thin layer is set shorter than a distance from the barrier electrode to the outer peripheral edge of the first thin layer. The present invention relates to a Schottky barrier semiconductor device, wherein the outer peripheral edge of the thin layer is located inside the outer peripheral edge of the first thin layer.

[Operation] In the above invention, when a reverse voltage is applied between the barrier electrode and the semiconductor region, a depletion layer based on a shutter barrier between the barrier electrode and the semiconductor region, a first thin layer and the semiconductor region are formed. And a depletion layer based on a fire barrier. Since the first thin layer surrounds the barrier electrode, both depletion layers are directly continuous when the first thin layer is adjacent to the barrier electrode, and when the guard ring is included,
This continues through the depletion layer of the pn junction. Both the barrier electrode and the first thin layer generate a shutter barrier between the semiconductor region and the first thin layer is a resistor, so that the potential is increased from the inner peripheral side to the outer peripheral side of the thin layer. A gradually changing potential gradient occurs. As a result, the depletion layer can be spread so that the electric field is not concentrated on the peripheral edge of the barrier electrode, and the breakdown voltage is significantly improved.

The second thin layer has a function of reducing reverse current. That is, the second
By providing such a thin layer, the breakdown voltage that occurs near the tip of the first thin layer is increased, and the reverse current flowing through the first thin layer is reduced due to the breakdown.

[First Embodiment] A shutter barrier diode according to a first embodiment of the present invention and a method for manufacturing the same will be described with reference to Figs.

In manufacturing the shutter barrier diode shown in FIG. 1, first, as shown in FIG. 2 (A), a semiconductor substrate 21 made of GaAs (gallium arsenide) is prepared. This semiconductor substrate 21 has a thickness of 300 μm and an impurity concentration of (1 to 3) ×
10 to 20 μm thick on the n ⁺ type region 22 of 10 ¹⁸ cm ⁻³
m, impurity concentration (1-2) × 10 ¹⁵ cm ⁻³ n-type region 23
It is an epitaxial growth.

Next, as shown in FIG. 2B, a Ti (titanium) thin layer 24 is formed on the entire upper surface of the n-type region 23 made of n-type GaAs by vacuum evaporation, and Al (aluminum) is further formed on the entire upper surface.
Layer 25 is continuously vacuum deposited. The Ti thin layer 24 has an extremely thin thickness of 50Å to 200Å (0.005 to 0.02 μm). The thickness of the Al layer 25 is about 2 μm and is 1 of the Ti thin layer 24.
It is more than 00 times. Further, Au is formed on the lower surface of the n ^{+ type} region 22.
An ohmic contact electrode 26 made of an alloy of (gold) -Ge (germanium) is formed by vacuum evaporation, and then 38.
Heat treatment is performed at 0 ° C. for 10 seconds.

Next, as shown in FIG. 2 (C), a part of the Al layer 25 is removed by photo-etching to leave the Al layer 25a corresponding to the shutter barrier electrode which becomes the main forward current path. Further, the Ti thin layer 24 is removed from the peripheral region of the chip by photo-etching, and the Ti thin layer 24a located under the Al layer 25a and the Ti thin layer 24 surrounding the Ti thin layer 24a are adjacent to each other.
b is left. Since the Ti thin layers 24a and 24b are extremely thin films even if Ti itself is a conductor, the sheet resistance is 20 to 20.
The resistance layer is 400 Ω / □, which is an order of magnitude higher than the Al layer 25a.

Next, heat treatment is performed in air at 300 ° C. for 30 minutes. As a result, as shown in FIG. 2D, the Ti thin layer 24b not covered with the Al layer 25a is oxidized to become the first titanium oxide thin layer 27. Ti thin layer 24 under Al layer 25a
Since a is masked by the Al layer 25a, it is not oxidized. The titanium oxide thin layer 27 has a layer thickness larger than that of the Ti thin layer 24b and has an approximate thickness of 75Å to 300Å, and also has a sheet resistance of about 1000 MΩ / □ and is a semi-insulating high resistance layer. , TiO which can be regarded as a perfect insulator
It is in a state close to ₂ (titanium dioxide).

Next, after removing the Al layer 25a by etching, as shown in FIG.
As shown in (E), Ti thin layer 24a, titanium oxide thin layer 2
7. A Ti thin layer 28 is vacuum-deposited on the upper surface of the n-type region 23. Subsequently, the Al layer 29 is vacuum-deposited on the upper surface of the Ti thin layer 28. The thickness of each of the Ti thin layer 28 and the Al layer 29 is Ti.
It is almost equal to the layer thickness of the thin layer 24 and the Al layer 25.

Next, as shown in FIG. 2 (F), a part of the Al layer 29 is removed by etching, and Al is made to correspond to the shutter barrier electrode.
The layer 29a remains. Further, the Ti thin layer 28 is removed from the peripheral region of the chip by photo-etching, and the Al layer 29a is removed.
The Ti thin layer 28a located under the lower layer and the Ti thin layer 28b surrounding and surrounding the Ti thin layer 28a are left. Ti thin layers 28a, 28
The sheet resistance of b is the same as that of the Ti thin layer 24a. Subsequently, heat treatment is performed in air at 275 ° C. for 25 minutes. As a result, as shown in FIG. 2G, the Ti thin layer 28b not covered with the Al layer 29a is oxidized to become the second titanium oxide thin layer 30. Ti thin layer 28a under Al layer 29a
The Al layer 29a is not oxidized because it is masked.
The second titanium oxide thin layer 30 has a layer thickness of 75 Å to 300 Å, which is larger than the layer thickness of the Ti thin layer 28b, and is almost the same as the first titanium oxide thin layer 27. I'm running. The second thin titanium oxide layer 30 has a lower degree of oxidation than the first thin titanium oxide layer 27. Therefore, the second titanium oxide thin layer 30 has a thickness of about 100 MΩ / □.
Although it is a semi-insulating high resistance film having a sheet resistance of 1), it is a thin layer having a lower resistance than the first titanium oxide thin layer 27. First and second thin titanium oxide layers 27, 3
0 is a so-called oxygen-poor titanium oxide TiO _x (x is 2) which has less oxygen than TiO ₂ which can be regarded as a perfect insulator.
It is thought that it is becoming smaller. Note that the second titanium oxide thin layer 30 has a larger degree of oxygen poor than the first titanium oxide thin layer 27.

Since both Al and Ti are metals that form a shutter barrier between GaAs and Al, the Al layer 29a and the Al layer 2 are
The electrode composed of two Ti thin layers 28a and 24a located under 9a will be referred to as a barrier electrode or a barrier metal electrode 31. As shown in FIG. 3, the two titanium oxide thin layers 27 and 30 are arranged so as to surround the barrier metal electrode 31. The two titanium oxide thin layers 27 and 30 are adjacent to the barrier metal electrode 31 and
Is electrically connected to. As shown in FIG. 2 (G), the outer peripheral edge of the first titanium oxide thin layer 27 and the outer peripheral edge of the second titanium oxide thin layer 30 do not coincide with each other. The outer peripheral edge of the thin metal layer 30 is located closer to the barrier metal electrode 31 than the outer peripheral edge of the first titanium oxide thin layer 27.

Then, as shown in FIG. 1, titanium oxide thin layers 27 and 3 are formed.
An insulating layer 32 covering 0 is provided to complete a semiconductor chip having a shutter barrier, that is, a power shutter diode diode chip. The insulating layer 32 is plasma C
A silicon oxide film formed by the VD method or the photo CVD method was suitable. Although not shown in the drawing, for example, a Ti layer and an Au layer are sequentially provided on the upper surface of the Al layer 29a, and this is used as a connecting electrode for the lead member.

FIG. 3 is a plan view of the chip in the state of FIG. 2 (G). To illustrate the dimensions of each part in FIG. 3, the barrier metal electrode 3
The width a of the second titanium oxide layer 30 is about 910 μm.
Has a width b of about 140 μm, a width c of the first titanium oxide thin layer 27 protruding from the second titanium oxide thin layer 30 is about 10 μm, and the tip of the first titanium oxide thin layer 27 and the n-type The width d with the edge of the region 23 is about 150 μm.

A curve A in FIG. 4 shows an example of reverse voltage-reverse current characteristics of the Schottky barrier diode of this embodiment. The reason why such characteristics are exhibited is unclear, but it is considered as follows. When the reverse voltage applied to the Schottky barrier diode is gradually increased from zero volt, an extremely minute saturation current I _S flows through the Schottky barrier diode as shown in the region I of FIG. This saturation current I _S is the same as the first shutter barrier based on the barrier metal electrode 31 and the first shutter barrier.
Flowing through a second shutter barrier based on titanium oxide thin layer 27 of. The reverse voltage application circuit is connected to the barrier metal electrode 31 serving as an anode electrode and the ohmic electrode 26 serving as a cathode electrode. Since a reverse voltage application circuit is not directly connected to the first and second titanium oxide thin layers 27 and 30, the first and second titanium oxide thin layers 27 and 30 are not connected.
The current passing through flows into the barrier metal electrode 31. here,
Since the first titanium oxide thin layer 27 has a higher resistance than the second titanium oxide thin layer 30, the saturation current I of the second Schottky barrier flowing laterally toward the barrier metal electrode 31. _S flows mainly through the second low-resistance titanium oxide thin layer 30. Further increase the reverse voltage to 100
At about 150 V, breakdown occurs in a plurality of minute regions near the outer peripheral edge of the first titanium oxide thin layer 27,
The reverse current increases stepwise as shown in region II of FIG. The reverse current I ₀ that accompanies this breakdown is the second titanium oxide thin layer 30 on the first titanium oxide thin layer 27.
In the overlapping portion, the barrier metal electrode 31 mainly flows through the second titanium oxide thin layer 30 which is a lower resistance layer than the first titanium oxide thin layer 27. In the conventional Schottky barrier diode, a large reverse current I ₀ flows due to the breakdown in this minute region, but a large reverse current I ₀ does not flow in the Schottky barrier diode according to the present invention. That is, since the first and second titanium oxide thin layers 27 and 30 are both high resistance layers, the current limitation due to the resistance of the first and second titanium oxide thin layers 27 and 30 works, and The current I ₀ is greatly suppressed.

The flow of the reverse current I ₀ causes a potential gradient between the first titanium oxide thin layer 27 and the second titanium oxide thin layer 30. Here, since the reverse current I ₀ mainly flows through the second thin titanium oxide layer 30, the potential gradient is mainly determined by the second thin titanium oxide layer 30. At the end of the region II, the potential difference between the end of the first titanium oxide thin layer 27 on the inner peripheral side in contact with the barrier metal electrode 31 and the end on the outer peripheral side far from the barrier metal electrode 31 is relatively large. growing. As a result, the potential difference between the outer peripheral end of the first titanium oxide thin layer 27 and the ohmic electrode 26 does not increase much even when the reverse voltage applied is increased. Therefore, no new breakdown occurs at the outer peripheral edge of the first titanium oxide thin layer 27. However, the breakdown already generated on the outer peripheral side of the first titanium oxide thin layer 27 is maintained as it is, and the reverse current I ₀ based on this breakdown flows mainly through the second thin titanium oxide layer 30. to continue.

In the region III, since no new breakdown occurs on the outer peripheral side of the first titanium oxide thin layer 27, the reverse current gradually increases as the reverse voltage increases, but a period in which the reverse current does not rapidly increase continues. become. During this period, the depletion layer 33 schematically shown in FIG.
In the n-type region 23 below the thin titanium oxide layer 27.
The potential difference between the first titanium oxide thin layer 27 and the n ^{+ -type} region 22 becomes smaller as it goes from the inner peripheral end to the outer peripheral end of the first titanium oxide thin layer 27. Therefore, the spread (the thickness in the vertical direction) of the depletion layer 33 also decreases from the inner peripheral side end toward the outer peripheral side end. Further, the surface of the n-type region 23 extending from the barrier metal electrode 31 to the end portion on the outer peripheral side of the first titanium oxide thin layer 27 is continuous as a shutter barrier. As a result, a gentle depletion layer 33 that can alleviate the electric field concentration is obtained, and the electric field concentration at the peripheral edge of the barrier metal electrode 31 is alleviated.

When the reverse voltage is about 250V, a portion exceeding the critical electric field strength Ecrit occurs between the peripheral edge of the barrier metal electrode 31 and the ohmic electrode 26, causing breakdown. As a result, the reverse current sharply increases as shown in region IV.

When the shutter barrier diode of this embodiment was used as a rectifying diode of a switching regulator having a switching frequency of 500 kHz, it was confirmed that a good rectifying operation with extremely little noise was generated. No reduction in the switching speed (high-speed response) due to the provision of the first and second thin titanium oxide layers 27 and 30 was observed.

Even when only the one corresponding to the first titanium oxide thin layer 27 surrounding the outer peripheral portion of the barrier metal electrode 31 is provided, high breakdown voltage is achieved. However, by providing the second titanium oxide thin layer 30 on the first titanium oxide thin layer 27 according to the present invention, a Schottky barrier diode having a small reverse current level can be realized. The curve B in FIG. 4 shows the reverse voltage-reverse current characteristics of the Schottky barrier diode whose breakdown voltage is increased by one thin layer of titanium oxide. As is clear from the comparison between this curve B and the curve A of this embodiment, the reverse current level of the Schottky barrier diode of this embodiment is smaller.

Although the reason why the reverse current level becomes small is not always clear, two phenomena can be read from FIG. One is, as is clear from the comparison of the region I, the saturation current I _S of the curve A.
Is smaller than the curve B. This is due to the fact that the degree of oxidation of the first thin titanium oxide layer 27 is increased, so that the second thin titanium oxide layer 27 based on
The barrier height φ _B of the
The relationship that the saturation current I _S becomes smaller as the barrier height φ _B becomes larger does not occur. The other reason is that the area II of the curve A is shifted to a higher pressure side than the area II of the curve B. That is, the vicinity of the outer peripheral edge of the first titanium oxide thin layer 27 (generally refers to the region from the outer peripheral edge of the second titanium oxide thin layer 30 to the outer peripheral edge of the first titanium oxide thin layer 27). The breakdown voltage at is improved. Therefore, when breakdown occurs in the above-mentioned minute region, if the applied reverse voltages are compared at the same level, the breakdown voltage near the outer peripheral edge of the first titanium oxide thin layer 27 increases, and And second titanium oxide thin layer 2
The potential difference between the inner peripheral edge and the outer peripheral edge of 7, 30 becomes small.
When this potential difference is small, the sheet resistance of the second titanium oxide thin layer 30 is similar to that in the case of the curve B in FIG. 4, and therefore the reverse current I ₀ in the region III is small.

The other effects of this embodiment are summarized as follows.

(1) The breakdown voltage can be increased and the high-speed response is good as compared with the conventional shutter barrier having a guard ring.

(2) A higher breakdown voltage is obtained and thermal instability of characteristics is eliminated compared to the conventional Shoutoki barrier diode having a field plate with an insulating layer interposed.

(3) Ti thin layers 24a and 28a provided directly under the Al layer 29a
Since the Ti thin layers 24b and 28b which are the extended portions of the Ti oxides are oxidized to obtain the titanium oxide thin layers 27 and 30, the desired titanium oxide thin layers 27 and 30 can be easily obtained. In addition, the barrier metal electrode 31 and the titanium oxide thin layers 27, 30
The electrical connection can be achieved easily and reliably.

[Second Embodiment] Next, a shutter barrier diode according to a second embodiment of the present invention shown in FIG. 6 will be described. However, the same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

The Schottky barrier diode shown in FIG. 6 has two titanium oxide thin layers 27 and 30 arranged in a ring shape on the outer periphery of the barrier metal electrode 31 similarly to the Schottky barrier diode of the first embodiment. We have realized a high breakdown voltage Schottky barrier diode with a small reverse current level. further,
The Schottky barrier diode shown in FIG. 6 has a large thickness first barrier metal electrode 31a in which a barrier metal electrode 31 is arranged in the center, and a thin second barrier metal electrode 31a surrounding the first barrier metal electrode 31a. And a barrier metal electrode 31b. The first barrier metal electrode 31a is composed of an Al layer 29a and two Ti thin layers 24a and 28a located under the Al layer 29a.
And the second barrier metal electrode 31b is composed of two Ti thin layers 24c and 28c. Ti thin layer 24c, 2
Reference numeral 8c is an extended portion of the Ti thin layers 24a and 28a, and titanium oxide thin layers 27 and 30 are Ti thin layers 2 and 2, respectively.
It is obtained by oxidizing the extended portions of 4c and 28c. By providing the thin second barrier metal electrode 31b, the electric field concentration point and the stress concentration point can be separated, the frequency of products having a specified breakdown voltage or less is reduced, and the breakdown voltage yield is improved.

Also, the upper titanium oxide thin layer 30 that determines the potential gradient
Is provided with a ring-shaped Ti thin layer 37 for potential equalization. The equipotential Ti thin layer 37 is obtained by oxidizing the Ti thin layer to obtain the titanium oxide thin layer 30 by leaving the Ti thin layer as it is without being partially oxidized. Since the ring-shaped Ti thin layer 37 for potential equalization has high conductivity, it can serve as an equipotential distribution region. As a result, it is possible to correct the non-uniformity of the potential distribution in plan view on the surface of the n-type region 23 to form a uniform depletion layer and improve the breakdown voltage yield.

[Modification]

The present invention is not limited to the above-mentioned embodiments, and the following modifications are possible, for example.

(1) The effective range of the sheet resistance of the titanium oxide thin layer 27 and the sheet resistance of the titanium oxide thin layer 30 varies depending on the structure and size of the semiconductor chip. Resistance is 10kΩ / □ to 1000Ω /
□, preferably from 50 MΩ / □ to 200 MΩ / □. Further, the sheet resistance of the lower titanium oxide thin layer 27 should be selected from 10 MΩ / □ to 10000 MΩ / □, and preferably 200 MΩ / □ to 3000 MΩ / □.

(2) When the width b + c of the titanium oxide thin layer 27 is about 10 μm or more, the effect of improving the withstand voltage appears, and when it is 30 μm or more, the effect becomes remarkable. But,
In order to increase the yield to obtain a predetermined breakdown voltage, 100
It is more desirable to design to be μm or more. Width b + c is 5
Even if it is set to 00 μm or larger, a sufficient breakdown voltage improving effect can be obtained. Therefore, there is no upper limit of the width b + c, but even if the width b + c is 500 μm or more, it is not possible to expect a proportional increase in the breakdown voltage, and there is a problem that the semiconductor chip becomes large. Therefore, width b
It is desirable that + c is in the range of 30 to 500 μm.

(3) The film thickness of the Ti thin layers 24 and 28 is controlled by the film thickness control, the oxidation temperature,
It should be more than 20Å considering the oxidation time. The upper limit is not limited as long as a predetermined sheet resistance can be obtained, but since the Ti thin layers 24 and 28 are thermally oxidized to obtain the titanium oxide thin layers 27 and 30, the oxidation temperature and the oxidation time are taken into consideration. Should be less than 300Å. Note that this upper limit can be further expanded if strong oxidation such as plasma oxidation is performed.

(4) Titanium oxide thin layer 2 by oxidizing Ti thin layers 24 and 28
The oxidation temperature for obtaining 7 and 30 is preferably 500 ° C. or lower, and is 380 ° C. or lower when using an Au-based electrode. The lower limit of the oxidation temperature is 200 ° C. or higher in the case of the thermal oxidation method, but it can be a low temperature of room temperature or lower in the case of the plasma oxidation. The oxidation time varies depending on the thickness of the Ti thin layers 24 and 28, the oxidation temperature, and the oxidizing atmosphere, but it is preferably within the range of 5 seconds to 2 hours.

(5) The titanium oxide thin layers 27 and 30 may be formed by vapor deposition of titanium oxide or sputtering.

(6) A titanium oxide thin layer is suitable as a thin layer having a high sheet resistance and producing a shock barrier, but it may be a thin oxide layer of a Ta (tantalum) -based material. Further, the Ti thin layers 24 and 28 and the titanium oxide thin layers 27 and 3 are formed.
0 may be added with In, Sn, or the like.

(7) It can also be combined with a guard ring composed of a p ^{+ type} region. In the example of FIG. 6, a p ^{+ type} region is formed below the boundary portion between the Ti thin layer 42C and the titanium oxide thin layer 27 and is separated from the first barrier metal electrode 31a. In this way, the resistance of the second barrier metal electrode 31b having a higher sheet resistance than that of the first barrier metal electrode 31a suppresses the forward current from flowing into the p ^{+ -type} region, and the high speed response is not deteriorated. It won't happen. When the high speed response is not a problem, a guard ring may be formed so as to be adjacent to the peripheral edge of the barrier metal electrode 31 shown in FIG. When the guard ring is formed, the shutter barrier formed by the barrier metal electrode and the shutter barrier formed by the titanium oxide thin layer are connected through the pn junction of the guard ring.

(8) III-V such as InP (indium phosphide) instead of GaAs
It can also be applied to a shutter barrier semiconductor device using a group compound or silicon.

(9) In the case of forming a shutter barrier semiconductor device in an integrated circuit, a planer is provided in which an n ^{+ type} region 22 is provided so as to surround the n type region 23 in an island shape, and an ohmic electrode 26 is provided on the surface side of the n type region 23. It may be a structure.

(10) The n-type region 23 and the n ^{+ -type} region 22 can be replaced with the p-type region.

〔The invention's effect〕

As described above, according to the present invention, it is possible to easily provide a high breakdown voltage semiconductor barrier semiconductor device having a small reverse current (leakage current).

[Brief description of drawings]

1 is a sectional view showing a shutter barrier diode according to the first embodiment of the present invention, and FIGS. 2 (A) to (G) are sectional views showing the shutter barrier diode in FIG. 1 in the order of manufacturing steps. FIG. 3 is a plan view showing the state of FIG. 2 (G), and FIG. 4 is a reverse voltage-reverse current of the shutter barrier diode of FIG. 1 and the shutter barrier diode having a thin titanium oxide layer as a single layer. FIG. 5 is a partially enlarged sectional view of a shutter barrier diode schematically showing a depletion layer, and FIG. 6 is a sectional view showing the shutter barrier diode of the second embodiment. 22 ... N ^{+ type} region, 23 ... N type region, 26 ... Ohmic electrode, 27 ... First titanium oxide thin layer, 30 ...
2nd titanium oxide thin layer, 31 ... Barrier metal electrode.

Claims (1)

[Claims] 1. A semiconductor region, a barrier electrode formed on the semiconductor region so that a Schottky barrier can be generated between the semiconductor region, and the semiconductor region on the semiconductor region so as to surround the barrier electrode. And is electrically connected to the barrier electrode, has a larger sheet resistance than the barrier electrode, and is formed so as to generate a Schottky barrier with the semiconductor region. A thin layer, which is disposed on the first thin layer and has a sheet resistance larger than that of the barrier electrode but smaller than that of the first thin layer and electrically connected to the barrier electrode. Second connected
And the distance from the barrier electrode to the outer peripheral edge of the second thin layer is set shorter than the distance from the barrier electrode to the outer peripheral edge of the first thin layer. A Schottky barrier semiconductor device, wherein an outer peripheral edge of the thin layer is located inside an outer peripheral edge of the first thin layer.