JP2002151520A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the crystallinity of an AlGaInP layer of a semiconductor device comprising a plurality of compound semiconductor layers including the AlGaInP layer and a hetero junction. SOLUTION: The semiconductor device comprises a laminate composed of an n+ type GaAs collector electrode lead out layer 102, an n-type GaAs collector layer 103, a p-type GaAs base layer 104, an n-type (AlxGa1-x)yIn1-yP (0.1<=x<=0.7, 0<=y<=1) emitter layer 105, and an n+ type GaAs emitter lead out layer 106 on a semi-insulative GaAs substrate 101. The laminate has first insulation regions 111 on one side and second insulation regions 112 on the other side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device having a plurality of compound semiconductor layers and a heterojunction.

[0002]

2. Description of the Related Art Compound semiconductor devices, such as transistors, made of compound semiconductors and capable of operating at high speed have been widely put into practical use in the field of mobile phones and the like.

At present, compound semiconductor devices mainly use GaAs.
s layer and Al _s Ga _{1 -s} As layer (0 ≦ s ≦ 1) layer (hereinafter, referred to as
Simply are constituted by referred to as AlGaAs layer), in order to improve the properties of the compound semiconductor device to operate at high speed at the time of high temperature, Ga _r In _1-r P layer (0 ≦ r ≦
1) layer (hereinafter simply referred to as GaInP layer) or (A
l _x Ga _1-x ) _y In _1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1)
It is useful to use a semiconductor layer having a larger band gap, such as (hereinafter simply referred to as an AlGaInP layer).

For example, a heterojunction bipolar transistor (HBT) is known as a typical compound semiconductor device. This is because the efficiency of injecting electrons from the emitter to the base can be increased by using a mixed crystal having a larger band gap than the base layer as the emitter layer.

In general, most HBTs use a GaAs layer as a base layer and an AlGaAs layer as an emitter layer. The AlGaAs layer has a larger band gap than the GaAs layer.
Since the lGaAs layer has substantially the same lattice constant as the GaAs layer, a high-quality epitaxial crystal having excellent crystallinity can be easily obtained.

However, when a mobile phone or a vehicle-mounted phone is used in a severe environment such as a high environmental temperature, etc., in order to realize high performance HBT characteristics, the emitter layer must be It is necessary to use a semiconductor layer having a larger band gap.

To this end, it is conceivable to use an AlGaInP layer having a larger band gap than the AlGaAs layer and capable of lattice matching with the GaAs layer as the emitter layer.

[0008]

By the way, AlGaI
In order to improve the crystallinity of the semiconductor layer composed of the nP layer, it is desirable that the semiconductor layer is grown at a high temperature of about 700 ° C. or more in metal organic chemical vapor deposition.

On the other hand, since the AlGaInP layer has a thermally unstable property, if the growth interface is an AlGaInP layer, the AlGaInP layer is exposed to a high-temperature atmosphere and the AlGaInP layer is exposed to a high-temperature atmosphere.
The flatness of the nP layer is impaired, making it difficult to obtain a good crystal film. In particular, when a semiconductor element having a buried layer is formed, it is necessary to thermally clean the regrowth interface for a certain period of time, so that there is a higher possibility that the flatness is impaired.

As described above, since it is difficult for the AlGaInP layer to have a good crystal film, there is a limitation in improving the characteristics of the semiconductor device having the AlGaInP layer.

In view of the above, an object of the present invention is to improve the crystallinity of an AlGaInP layer in a semiconductor device having a plurality of compound semiconductor layers including an AlGaInP layer and a heterojunction.

[0012]

In order to achieve the above object, a first semiconductor device according to the present invention is directed to a semiconductor device having a plurality of compound semiconductor layers and a heterojunction, and a plurality of compound semiconductors. The layer is (Al _x Ga _{1 -x} ) _y In
_It has an AlGaInP semiconductor layer represented by _1-y P (0.1 ≦ x ≦ 0.7, 0 ≦ y ≦ 1).

The first semiconductor device preferably further includes a buried layer, and the AlGaInP semiconductor layer is preferably adjacent to the buried layer.

A second semiconductor device according to the present invention includes a plurality of compound semiconductor layers and a heterojunction,
For a semiconductor device in which a semiconductor laser element having an active layer and a cladding layer is stacked on the same substrate, a plurality of compound semiconductor layers are composed of (Al _x Ga _{1 -x} ) _y In _{1 -y} P (however,
AlG represented by 0.1 ≦ x ≦ 0.7, 0 ≦ y ≦ 1)
It has an aInP semiconductor layer.

Preferably, the second semiconductor device further includes a buried layer, and the AlGaInP semiconductor layer is adjacent to the buried layer.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment A semiconductor device according to a first embodiment of the present invention will be described below with reference to FIG.

FIG. 1 shows a cross-sectional structure of a compound semiconductor device comprising a bipolar transistor (HBT) having a hetero junction as a first embodiment.

As shown in FIG. 1, on a semi-insulating GaAs substrate 101, a collector electrode extraction layer 102 composed of an n ⁺ -type GaAs layer, a collector layer 103 composed of an n-type GaAs layer, and a base composed of a p-type GaAs layer. A stacked body including a layer 104, an emitter layer 105 made of an n-type AlGaInP layer, and an emitter electrode extraction layer 106 made of an n ⁺ -type GaAs layer is formed, and a first insulating region is provided on one side surface of the stacked body. A second insulating region 112 is provided on the other side surface of the stacked body. A collector terminal 107 is connected to the collector electrode extraction layer 102, a first base terminal 108 and a second base terminal 109 are connected to the base layer 104, and an emitter terminal 1 is connected to the emitter electrode extraction layer 106.
10 are connected.

The collector electrode extraction layer 102 is provided for the purpose of extracting the collector electrode and reducing the collector resistance.

The first insulating region 111 and the second insulating region 112 are formed by sequentially growing the collector electrode extraction layer 102, the collector layer 103, the base layer 104, the emitter layer 105, and the emitter electrode extraction layer 106 by epitaxial growth. It is formed by selectively implanting protons and the like.

The electrode for connecting the collector terminal 107 to the collector electrode extraction layer 102 is the collector layer 10.
3. A portion of the base layer 104, the emitter layer 105, and the emitter electrode extraction layer 106 is selectively removed by etching to expose the collector electrode extraction layer 102, and then a metal film is formed on the exposed portion to form an ohmic electrode. Make contact.

The electrodes for connecting the first base terminal 108 and the second base terminal 109 to the base layer 104 are:
After the emitter layer 105 and a part of the emitter electrode extraction layer 106 are selectively removed by etching to expose the base layer 104, a metal film is formed on the exposed portion to form an ohmic contact.

Here, the emitter layer 105 is made of AlG
An aInP layer is used. Since the AlGaInP layer has a band gap larger than that of the GaAs layer and can perform lattice matching with the GaAs layer, the efficiency of electron injection from the emitter layer 105 to the base layer 104 can be increased.

However, in order to obtain such characteristics, a high quality AlGaIn
It is necessary to form a P layer. In order to form a high quality AlGaInP layer by metal organic chemical vapor deposition, 70
A high growth temperature of about 0 ° C. or higher is required. On the other hand, Al
The GaInP layer has the property that it is thermally unstable, and the flatness of the growth interface may be impaired at high temperatures.

Constituting the emitter layer 105 (Al _x Ga)
_1-x ) In the epitaxial growth of the _y In _1-y P layer, x
Is smaller than 0.1, the thermal instability is so large that it is difficult to realize a high-quality epitaxially grown layer by growth at a high temperature. This is because the bond between Ga and P is weaker than the bond between Al and P.
It is considered that the smaller the component of l, the more easily P in the grown film is released.

On the other hand, when x is larger than 0.7, Al
It is difficult to obtain a high-quality epitaxially grown layer because the crystallinity tends to deteriorate due to the increase in the amount of the component.

Therefore, high quality (Al _x Ga _{1 -x} ) _y In _{1 -y}
In order to obtain a P layer, x may be set to 0.1 ≦ x ≦ 0.7. To achieve lattice matching with the GaAs layer, y
Is preferably set between 0.45 and 0.55.

As described above, as the emitter layer 105,
AlGa having a band gap larger than that of the AlGaAs layer
By using the InP layer, it is possible to realize an HBT with high electron injection efficiency from the emitter layer 105 to the base layer 104.

Further, by setting _{x of} the (Al _x Ga _{1 -x} ) _y In _{1 -y} P layer to 0.1 ≦ x ≦ 0.7, a high quality epitaxial crystal film can be easily obtained. By using a high-quality epitaxial crystal film for the emitter layer 105, a high-quality HBT having a large band gap can be easily realized.

(Second Embodiment) A semiconductor device according to a second embodiment of the present invention will be described below with reference to FIG.

FIG. 2 shows a sectional structure of a compound semiconductor device composed of a high electron mobility field effect transistor (HEMT) in which a red semiconductor laser is integrated on the same substrate as a second embodiment.

As shown in FIG. 2, on a semi-insulating GaAs substrate 201, a semiconductor layer 202 composed of an n-type AlGaInP layer, an n-type cladding layer 203 composed of an n-type AlGaInP layer, and an active layer 204 composed of a GaInP layer , P-type A
A p-type cladding layer 205 made of an lGaInP layer is sequentially formed, and an n ⁺ -type AlGaI
Source region 206 made of nP layer and n ⁺ -type AlGaI
A drain region 207 made of an nP layer is formed.
The p-type cladding layer 205 is connected to a hole injection electrode / gate electrode 208 of the semiconductor laser, the source region 206 is connected to an electron injection electrode / source electrode 209 of the semiconductor laser, and the drain region Reference numeral 207 denotes an electron injection electrode / drain electrode 210 of a semiconductor laser.
Is connected. Reference numeral 211 denotes a two-dimensional electron gas generation region formed by a heterojunction between the semi-insulating GaAs substrate 201 and the n-type AlGaInP layer 202.

Hereinafter, a method for manufacturing the compound semiconductor device according to the second embodiment will be described.

First, on a semi-insulating GaAs substrate 201,
a semiconductor layer 202 composed of an n-type AlGaInP layer;
n-type cladding layer 203 made of lGaInP layer, GaI
An active layer 204 made of an nP layer and a clad layer 205 made of a p-type AlGaInP layer are sequentially crystal-grown.

Next, the p-type cladding layer 205 and the active layer 20
4 and a part of the n-type cladding layer 203 are connected to the semiconductor layer 20.
Etch until 2 is exposed.

Next, silicon ions are implanted into the semiconductor layer 202 exposed by the etching until the semiconductor layer 202 reaches the semi-insulating GaAs substrate 201, whereby n ⁺
A source region 206 and a drain region 207 made of a type AlGaInP layer are formed.

Next, an electrode connecting the hole injection electrode / gate electrode 208 of the semiconductor laser to the p-type cladding layer 205, an electrode connecting the electron injection electrode / source electrode 209 of the semiconductor laser to the source region 209, and An electrode for connecting the electron injection / drain electrode 210 to the drain electrode is formed.

As described above, when an optical device is integrated on an electronic device, it is important to keep the crystallinity of a semiconductor laser, which is an optical device, at high quality. In the second embodiment, a high-quality semiconductor laser is used. The flatness of the semiconductor layer 202 composed of an n-type AlGaInP layer, which is the base of the laser structure, is important.

(Al _x Ga _{1 -x} ) _y to become the semiconductor layer 202
When x of the In _1-y P layer is smaller than 0.1, thermal instability is considerably large, so that it is difficult to realize high-quality epitaxial growth under high-temperature growth.

On the other hand, when x is larger than 0.7, Al
, The high quality epitaxial growth is difficult to obtain because the crystallinity tends to deteriorate.

Therefore, high-quality (Al _x Ga _{1 -x} ) _y In _{1 -y}
In order to obtain a P layer, it is necessary to set x to 0.1 ≦ x ≦ 0.7. Further, y is preferably set between 0.45 and 0.55 in order to achieve lattice matching with the GaAs layer.

As described above, in order to realize a HEMT in which the semiconductor laser elements are integrated on the same substrate, _{x of} the (Al _x Ga _{1 -x} ) _y In _{1 -y} P layer constituting the electronic device is determined. By setting 0.1 ≦ x ≦ 0.7, it is possible to easily obtain a high-quality epitaxial crystal film and to obtain the flatness necessary for forming a semiconductor laser structure with high quality crystallinity. Becomes

[0043]

In the first semiconductor device according to the present invention, the emitter layer is made of (Al _x Ga _{1 -x} ) _y In _{1 -y} P (0.1 ≦ x ≦ 0.7, 0 ≦ y A represented by ≦ 1)
With the use of the 1GaInP semiconductor layer, a high-quality emitter layer having a large band gap difference from the GaAs layer can be obtained, so that the efficiency of electron injection from the emitter region to the base region can be greatly increased.

Further, in the second semiconductor device according to the present invention, the semiconductor layer of the electronic device is (Al _x Ga _{1 -x} ) _y
In _1-y P (however, 0.1 ≦ x ≦ 0.7, 0 ≦ y ≦ 1)
By using an AlGaInP semiconductor layer represented by the following formula, integration of a high-quality semiconductor laser and an electronic device becomes possible.

[Brief description of the drawings]

FIG. 1 is a sectional view of a compound semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a compound semiconductor device according to a second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 101 semi-insulating GaAs substrate 102 collector electrode extraction layer 103 collector layer 104 base layer 105 emitter layer 106 emitter electrode extraction layer 107 collector terminal 108 first base terminal 109 second base terminal 110 emitter terminal 111 first element isolation insulation Region 112 second element isolation insulating region 201 semi-insulating GaAs substrate 202 semiconductor layer 203 n-type cladding layer 204 active layer 205 p-type cladding layer 206 source region 207 drain region 208 hole injection electrode and gate electrode of semiconductor laser 209 semiconductor laser Injection electrode / source electrode 210 of semiconductor laser Electron injection electrode / drain electrode 211 Two-dimensional electron gas generation region

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) H01L 21/338 29/812 H01S 5/026 F term (Reference) 5F003 BA09 BA92 BC08 BE04 BE90 BF06 BM02 BM03 BP32 5F045 AB10 AB17 AB18 AF04 BB12 CA02 CA07 CA12 DA52 DA63 HA15 5F073 AA04 AB21 CA14 DA05 5F102 GA19 GB01 GC01 GD01 GJ05 GK04 GL04 GL08 GM04 GQ01 HC01

Claims (4)

[Claims] 1. A semiconductor device comprising a plurality of compound semiconductor layers and a heterojunction, wherein the plurality of compound semiconductor layers are (Al _x Ga _{1 -x} ) _y In
A semiconductor device comprising an AlGaInP semiconductor layer represented by _1-y P (0.1 ≦ x ≦ 0.7, 0 ≦ y ≦ 1). 2. The semiconductor device according to claim 1, further comprising a buried layer, wherein the AlGaInP semiconductor layer is adjacent to the buried layer. 3. A semiconductor device comprising a plurality of compound semiconductor layers and a heterojunction, and a semiconductor laser element having an active layer and a cladding layer laminated on the same substrate, wherein the plurality of compound semiconductors are provided. The layer is (Al _x Ga
_1-x ) _y In _1-y P (However, 0.1 ≦ x ≦ 0.7, 0 ≦ y
≦ 1) A semiconductor device having an AlGaInP semiconductor layer represented by the formula: 4. The semiconductor device according to claim 3, further comprising a buried layer, wherein the AlGaInP semiconductor layer is adjacent to the buried layer.