JP3202264B2 - Magnetic-sensitive semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetically sensitive semiconductor device, and more particularly, to a magnetic sensitive semiconductor device having a Hall element section and a field effect transistor section (hereinafter referred to as "FET section"). And a semiconductor device that outputs an output voltage.

[0002]

2. Description of the Related Art Conventionally, as this type of magnetically sensitive semiconductor device, there is one shown in FIGS. 3 and 4 (FIG. 4 shows a cross section taken along line IV-IV in FIG. 3). As shown in these figures, this magnetically sensitive semiconductor device has a semi-insulating GaAs structure.
On a substrate 21, a Hall element section 200 and an FET section 201 are provided. The above-mentioned Hall element section 200 is formed on the GaAs substrate 2.
1 has an n-type active layer 22 formed by implanting Si in a cross shape. The active layer 22 has a carrier
(Here, electrons) is a layer in which the carrier concentration is 1
It is set to 0 ¹⁷ cm ⁻³ (at this time, the mobility of the carrier is about 5000 cm ² / V · sec). Each of the cross-shaped ends of the active layer 22 is composed of three layers of Au-Ge / Ni / Au, and input portions 23a and 23b and output portions 24a and 24b that make ohmic contact with the active layer 22 are alternately formed. Is provided. The FET section 201 includes an input section 23a, a current correction section 25 provided near the input section 23a, and a gate 2 provided between the input section 23a and the current correction section 25.
It consists of six. The current correction unit 25 intersects with the portion of the active layer 22 near the input unit 23a, and makes the current flowing through the input unit 23a uniform. The gate 26 has a metal-semiconductor contact with the active layer 22, and controls an input current flowing through the input section 23a. For example, when the left input section 23b is grounded and a positive voltage is applied to the right input section 23a, the input current flowing between the input sections 23a and 23b is controlled by adjusting the voltage applied to the gate 26. can do.

When a magnetic field is applied to the magneto-sensitive semiconductor device, the Hall element unit 200 outputs an output voltage corresponding to the strength of the applied magnetic field and the input current flowing between the input units 23a and 23b to the output units 24a and 24b. Output during 24b. Here, since the input current can be controlled by the voltage applied to the gate 26 as described above, the output voltage of the Hall element unit 200 can be controlled by the voltage applied to the gate 26. Therefore, this magnetically sensitive semiconductor device does not require an external control circuit, and can perform a constant current operation and a switching operation by itself. There is something.

[0004]

However, the above-mentioned conventional magnetically sensitive semiconductor device has a problem that the sensitivity to an applied magnetic field is not sufficient and the switching speed is slow.

An object of the present invention is to provide a magnetically sensitive semiconductor device which can improve the sensitivity to an applied magnetic field and the switching speed.

[0006]

In order to achieve the above object, the present invention comprises a Hall element section and a HEMT section, wherein the output voltage generated by the Hall element section in response to an applied magnetic field is controlled by the HEMT section. In a magnetically sensitive semiconductor device that outputs a signal, a undoped GaAlAs layer, an n-type GaAlAs layer, and an n-type GaAs layer are sequentially laminated on a semi-insulating GaAs substrate, and a cross-shaped mesa portion formed by mesa-etching the above layers. The active layer that constitutes the Hall element portion,
The HEMT portion is formed on one end of the mesa portion and is in ohmic contact with the n-type GaAs layer; the input portion includes a two-dimensional electron gas layer formed at an interface between the GaAs substrate and the undoped GaAlAs layer; A current correcting section provided on the mesa section with a gap between the input section and the n-type in the gap between the input section and the current correcting section so that a current flowing through the input section is uniform. From GaAs layer to n-type Ga
A groove formed so as to reach the AlAs layer; and a gate provided at the bottom of the groove to make a metal-semiconductor contact with the n-type GaAlAs layer. Is characterized in that the electron concentration is controlled.

Here, HEMT (High Electron Mobility Transistor) means a field effect transistor that controls the two-dimensional carrier gas concentration at the gate.

[0008]

In general, a Hall voltage V generated by a Hall element portion is obtained.
Assuming that the applied magnetic flux density is B and the magnitude of the drive current is I, н is expressed as Vн = KнIB (1). Here, K н (called product sensitivity) is an amount determined by the physical properties of the active layer constituting the Hall element portion and the element shape, and increases as the carrier mobility increases and the thickness of the active layer decreases. . Therefore, when the active layer constituting the Hall element portion is formed of a two-dimensional carrier gas layer, the mobility of carriers in the two-dimensional carrier gas layer is
This is larger than in the case of the conventional single-layer structure (about 5000 cm ² / V · sec). For example, the electron mobility of a two-dimensional electron layer composed of a GaAlAs / GaAs heterojunction is about 7000 cm.
² / V · sec. Moreover, the thickness of the two-dimensional carrier gas layer is at least one order of magnitude thinner than the active layer formed by conventional ion implantation. Therefore, the sensitivity to the applied magnetic field is improved as compared with the related art. Also, the FET section is HEMT
, The switching speed is faster than that of the conventional FET unit. Therefore, the switching speed of the magnetically sensitive semiconductor device is improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a magnetic-sensitive semiconductor device according to the present invention will be described in detail with reference to embodiments.

FIG. 1 shows a plane pattern of a magnetically sensitive semiconductor device according to one embodiment, and FIG. 2 shows a cross section taken along line II-II in FIG. This magnetically sensitive semiconductor device is made of semi-insulating GaAs.
s On the substrate 1, a Hall element unit 100 and a HEMT unit (FET
(Unit) 101. The Hall element unit 100 includes:
A cross-shaped mesa 6 is provided on the surface of the semi-insulating GaAs substrate 1. The mesas 6 are formed on the GaAs substrate 1 by an epitaxial growth method.
An lAs layer 3 and an n-type GaAs layer 4 are sequentially stacked, and these layers 2, 3,.
4 is formed by mesa etching. With this structure, a two-dimensional electron gas layer 5 can be formed as an active layer at the heterojunction interface 1a between the GaAs substrate 1 and the undoped GaAs layer 2 (on the GaAs 1 substrate side). The electron mobility of the two-dimensional electron gas layer 5 is about 7,000 cm ² / V · sec. On each of the cross-shaped ends of the mesa section 6, Au
The input portions 7a and 7b and the output portions 8a and 8b which are composed of three layers of -Ge / Ni / Au and make ohmic contact with the n-type GaAs layer 4 are provided alternately. The HEMT unit 101 includes the input unit 7
a and a current correction unit 10 provided near the input unit 7a.
And a gate 9 provided between the input unit 7a and the current correction unit 10. The current correction unit 10 intersects with a portion of the mesa unit 6 near the input unit 7a, and makes the current flowing through the input unit 7a uniform. The gate 9 is provided at the bottom of the recess groove 11 extending from the surface of the n-type GaAs layer 4 to the surface of the n-type GaAs layer 3.
By contacting the semiconductor, the electron concentration of the two-dimensional electron gas layer 5 is controlled. For example, when the left input section 7b is grounded and a positive voltage is applied to the right input section 7a in the figure, the input section 7a,
The input current flowing between 7b can be controlled at high speed.

When a magnetic field is applied to the magneto-sensitive semiconductor device, the Hall element unit 100 outputs an output voltage corresponding to the strength of the applied magnetic field and the input current flowing between the input units 7a and 7b to the output units 8a and 8b. Output during 8b. Here, since the input current can be controlled by the voltage applied to the gate 9 as described above, the output voltage of the Hall element unit 100 can be controlled by the voltage applied to the gate 9. Therefore, like the conventional magnetically sensitive semiconductor device, this magnetically sensitive semiconductor device does not require an external control circuit, and can perform a constant current operation and a switching operation by itself.

Moreover, the electron mobility (about 7000 cm ² / V · sec) of the two-dimensional electron gas layer 5 is higher than that of the conventional active layer having a single-layer structure (about 5000 cm ² / V · sec). big,
In addition, the thickness of the two-dimensional carrier gas layer is at least one order of magnitude thinner than the active layer formed by conventional ion implantation. Therefore, the sensitivity to the applied magnetic field is improved as compared with the related art. Further, since the FET unit 101 is made of HEMT, the switching speed is faster than that of the conventional FET unit. Therefore, the switching speed of the magnetically sensitive semiconductor device is improved.

[0013]

As is clear from the above, according to the magneto-sensitive semiconductor device of the present invention, the sensitivity to the applied magnetic field and the switching speed can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a plane pattern of a magnetically sensitive semiconductor device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a cross-sectional structure of the magnetically sensitive semiconductor device.

FIG. 3 is a diagram showing a planar pattern of a conventional magnetically sensitive semiconductor device.

FIG. 4 is a diagram showing a cross-sectional structure of the magnetically sensitive semiconductor device.

[Explanation of symbols]

Reference Signs List 1 semi-insulating GaAs substrate 1a heterojunction interface 2 undoped GaAlAs layer 3 n-type GaAs
lAs layer 4 n-type GaAs layer 5 two-dimensional electron gas layer 6 mesa section 7a, 7b input section 8a, 8b output section 9 gate 10 current correction section 11 recess groove 100 hall element section 101 HE
MT section

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 43/06 G01R 33/07 G11B 5/37

Claims (1)

(57) [Claims] A semi-insulating GaAs substrate, comprising: a Hall element section and a HEMT section, wherein the output voltage generated by the Hall element section in response to an applied magnetic field is output while being controlled by the HEMT section. Undoped GaAlAs layer on top, n-type G
aAlAs layer and an n-type GaAs layer are laminated in this order, and each layer is provided with a cross-shaped mesa portion formed by mesa etching. The active layer constituting the Hall element portion is formed of the GaAs substrate and the undoped GaAlAs layer. The HEMT section is formed on one end of the mesa section and is in ohmic contact with the n-type GaAs layer. The HEMT section uniformly distributes a current flowing through the input section. A current correcting portion provided on the mesa portion with a gap between the input portion and the n-type Ga in a gap between the input portion and the current correcting portion.
A groove formed so as to reach the n-type GaAlAs layer from the As layer; and a gate provided at the bottom of the groove to make a metal-semiconductor contact with the n-type GaAlAs layer. A magnetically sensitive semiconductor device wherein the electron concentration of a two-dimensional electron gas layer is controlled.