JPH05299358A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To provide the manufacturing method of semiconductor device capable of forming III-V compound semiconductor layer excellent both in the crystallinity and the surface homology on a silicon substrate. CONSTITUTION:The title manufacturing method is composed of an oxide film removing step (b) removing the oxide film on the surface of a silicon substrate at a first temperature, a low temperature deposited film formation step (c) forming the low temperature deposited film of III-V compound semiconductor on the silicon substrate at a second temperature lower than the first temperature as well as a single crystal film depositing step (d) depositing a single crystal film of III-V compound semiconductor on the low temperature deposited film during the temperature discending time and starting the leading-in step of the group V base gas when the temperature attains a specific higher level than the third temperature in the single crystal film depositing step.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a silicon substrate on which III-
The present invention relates to a method for manufacturing a semiconductor device for forming a V-group compound semiconductor crystal layer.

[0002]

2. Description of the Related Art Recently, II such as GaAs has been formed on a silicon substrate.
Research and development of a crystal growth technique for growing a crystal layer of an IV compound semiconductor have been actively conducted. Since a silicon substrate is low in manufacturing cost, a large-diameter substrate can be easily manufactured, and is also excellent in strength, it is possible to form a large-diameter semiconductor substrate on which a compound semiconductor layer is formed. If possible, a large amount of compound semiconductor elements can be formed on this semiconductor substrate.

As a conventional method for growing a III-V group compound semiconductor crystal on a silicon substrate, after heat treating the silicon substrate in an atmosphere of a reducing gas and a V group-based gas, the III-V group compound semiconductor is grown at a low temperature. A method is known in which a low temperature growth layer is first formed, and then a III-V group compound semiconductor is epitaxially grown on the low temperature growth layer. However, by this conventional method, III is formed on a silicon substrate offset in the [011] direction from the (100) plane.
When the -V group compound semiconductor layer is grown, the major axis direction of the etch pits formed by KOH treatment of the grown compound semiconductor layer is perpendicular to the offset direction. When the long axis direction of the etch pits of the compound semiconductor layer formed on the offset silicon substrate is perpendicular to the offset direction, the grown compound semiconductor layer is inferior in surface morphology and crystallinity. It is known that there is a phenomenon. As described above, the conventional method cannot form a compound semiconductor layer excellent in surface morphology and crystallinity.

As a method for solving the above problems of the conventional method, there is a method described in Japanese Patent Application Laid-Open No. 2-175690. In this method, after a silicon substrate is heat-treated in a reducing gas atmosphere, a group V gas is first introduced at a low temperature to first form a low temperature growth layer of a III-V compound semiconductor, and then this low temperature growth layer is formed. A III-V group compound semiconductor is epitaxially grown thereon.

According to this method, the crystallinity of the grown compound semiconductor layer is improved as compared with the conventional method.

[0006]

However, according to the method described in Japanese Patent Laid-Open No. 2-175690, although the crystallinity of the grown compound semiconductor layer is improved, the silicon substrate is heat-treated in a reducing gas atmosphere. After that, there is a problem that the surface of the silicon substrate is contaminated before the low temperature growth layer is formed, and the surface morphology of the grown compound semiconductor layer is deteriorated.

An object of the present invention is to provide a method of manufacturing a semiconductor device capable of forming a group III-V compound semiconductor layer excellent in crystallinity and surface morphology on a silicon substrate.

[0008]

SUMMARY OF THE INVENTION The above object is to remove an oxide film on the surface of a silicon substrate at a first temperature in a method of manufacturing a semiconductor device in which a III-V compound semiconductor crystal layer is formed on a silicon substrate. And a group III-based gas and a group V-based gas at a second temperature lower than the first temperature while introducing a group III-V gas on the silicon substrate.
A low temperature growth film forming step of forming a low temperature growth film of a group compound semiconductor, and a third temperature higher than the second temperature and lower than the first temperature, the group III gas and the group V gas. And a single crystal film growing step of growing a single crystal film of a III-V group compound semiconductor on the low temperature growth film, the step of removing the oxide film and the low temperature growth film forming step. The introduction of the group V system gas is started at the time when a predetermined temperature lower than the first temperature and higher than the third temperature is reached during the temperature decrease from the first temperature to the second temperature. And a method for manufacturing a semiconductor device.

[0009]

According to the present invention, during the temperature decrease from the first temperature to the second temperature between the oxide film removing step and the low temperature growth film forming step, the temperature is lower than the first temperature and the single crystal film growth step is performed. Since the introduction of the group V gas is started when the temperature reaches a predetermined temperature higher than the third temperature, contamination of the surface of the silicon substrate before the low temperature growth layer is formed is prevented, and the crystallinity is also improved. It is possible to form a III-V compound semiconductor layer that is also excellent in terms of surface morphology.

[0010]

EXAMPLE A method of manufacturing a semiconductor device according to an example of the present invention will be described with reference to FIG. In this embodiment, a GaAs layer is formed as a III-V group compound semiconductor on a silicon substrate using a MOCVD device. First, the silicon substrate 10
Raise the temperature to 00 ° C. Then, while maintaining the temperature at 1000 ° C., the temperature is maintained at about 1 ° C. in a reducing gas atmosphere such as hydrogen gas.
Heat treatment for 0 minutes. As a result, the oxide film on the surface of the silicon substrate is removed (oxide film removing step). At this time III
Neither group gas TMG (trimethylgallium) nor group V gas AsH ₃ (arsine) is introduced.

Next, the temperature is lowered from 1000 ° C. to 450 ° C. which is the processing temperature in the low temperature growth film forming step. The introduction of AsH ₃ , which is a group V gas, is started until the temperature drops from 1000 ° C. to 650 ° C. which is the processing temperature of the single crystal growth step. In the present embodiment, the introduction start time of AsH ₃ which is a group V gas is set to be a point from when the processing temperature of the oxide film removing step is 1000 ° C. to when the processing temperature of the single crystal growing step is 650 ° C. There are features.

It is desirable that the introduction of AsH ₃ which is a group V gas be started not immediately after the oxide film removing step but from 800 ° C. to 650 ° C. which is the processing temperature of the single crystal growing step. .. If the introduction of AsH ₃ which is a group V gas immediately after the oxide film removal step is started, crystals having different crystal orientations are likely to be mixed in the grown GaAs layer, whereas the introduction start time of AsH ₃ is 800 ° C. GaAs with a single crystal orientation when it is lower than
This is because layers can be obtained.

Further, the temperature is lowered while introducing AsH ₃ to 45
When the temperature reaches 0 ° C., introduction of TMG, which is a group III gas, is also started, and formation of a low temperature growth film of GaAs is started on the silicon substrate. While keeping the temperature at 450 ° C, AsH ₃ and TMG were introduced for about 1 minute, and about 20 minutes were put on the silicon substrate.
A low-temperature grown film of 0 nm thick GaAs is formed. Next, A
After the introduction of TMG is stopped while introducing sH ₃ , the treatment temperature is raised. When the temperature reaches 650 ° C., which is the processing temperature in the single crystal growth process, the introduction of TMG, which is a group III gas, is restarted, and GaA is formed on the low temperature growth film on the silicon substrate.
The single crystal film of s is epitaxially grown. Temperature 65
AsH ₃ and TMG for about 40 minutes while maintaining at 0 ℃
Is introduced to form a GaAs single crystal film having a thickness of about 3 μm on the silicon substrate.

Next, after stopping the introduction of TMG, the processing temperature is lowered, and after the temperature drops to some extent, the introduction of AsH ₃ is stopped and the formation of the GaAs layer on the silicon substrate is completed. According to the method for manufacturing the semiconductor device of the present embodiment,
Contamination of the surface of the silicon substrate before formation of the low temperature growth layer was prevented, and a GaAs layer excellent in crystallinity and surface morphology could be formed. The result of observing the surface of the GaAs layer with an optical microscope is shown in FIG. For comparison, the result of observing the surface of the GaAs layer formed by the conventional method described in Japanese Patent Laid-Open No. 2-175690 with an optical microscope is shown in FIG. As is clear from comparison between FIG. 2 and FIG. 3, the GaAs formed according to the present embodiment.
It can be seen that the surface morphology of the layer is improved compared to conventional methods.

In order to confirm that the surface morphology and crystallinity were improved, the method of this example was used (10
The GaAs layer is grown on a silicon substrate offset in the [011] direction from the (0) plane, and this GaAs layer is KOH.
Processed to form etch pits. As a result, GaAs
It was found that the major axis direction of the etch pit formed in the layer was almost parallel to the offset direction of the silicon substrate, and the surface morphology and crystallinity were improved.

The present invention is not limited to the above embodiment, but various modifications can be made.
It is possible. For example, in the above embodiment, a III-V group compound
Although GaAs was formed on a silicon substrate as a semiconductor,
Other III-V compound semiconductors described below for the method of the present invention
It may be applied to body formation. For example, GaP, GaS
b, AlAs, AlP, AlSb, InAs, InP,
InSb, etc., Al_XGa_1-XAs, Al_XGa
_1-XP, Al_XGa_1-XSb, In_XGa_1-XAs, I
n_XGa_1-XP, In_XGa_{1- X}Sb, In_XAl_1-X
As, In_XAl_1-XP, In_XAl_1-XSb, GaA
s_XP_1-X, GaAs_XSb_1-X, GaP_XSb_1-X,
AlAs_XP_1-X, AlAs_XSb_1-X, AlP_XSb
_1-X, InAs_XP_1-X, InAs_XSb_1-X, InP
_XSb_1-XTernary mixed crystals such as Ga and Ga_1-XAl_XAs_1-YP
_Y, Ga_1-XAl _XP_1-YSb_Y, Ga_1-XAl_XAs
_1-YSb_Y, In_1-XAl_XAs_1-YP_Y, In_1-XA
l_XP_1-YSb_Y, In_1-XAl_XAs_1-YSb_Y, I
n_1-XGa _XAs_1-YP_Y, In_1-XGa_XP_1-YSb
_Y, In_1-XGa_XAs_1-YSb_Y, (Ga_1-XA
l_X)_YIn_1-YP, (Ga_1-XAl_X)_YIn_1-YA
s, (Ga_1-XAl_X)_YIn_1-YSb, Al (As
_1-XP_X)_YSb_1-Y, Ga (As _1-XP_X)_YSb
_1-Y, In (As_1-XP_X)_YSb_1-YQuaternary mixed crystal, etc.
The present invention can be applied to the formation of

In the above embodiment, the hydride gas AsH ₃ is used as the group V gas, but a halide gas AsCl ₃ may be used. As the V group gas of P and Sb, hydride gas PH ₃ , SbH ₃ may be used, or halide gas PCl ₃ , SbCl ₃ ,
SbCl ₄ may be used. Furthermore, vapors of solid As, solid P, and solid Sb may be used as the group V gas.

[0018]

As described above, according to the present invention, the temperature is lowered from the first temperature to the second temperature between the oxide film removing step and the low temperature growth film forming step, and the temperature is lower than the first temperature. Since the introduction of the group V gas is started at the time when the temperature reaches a predetermined temperature higher than the third temperature in the single crystal film growth step, contamination of the surface of the silicon substrate before the low temperature growth layer is formed is prevented. , Excellent in crystallinity and surface morphology III-
A group V compound semiconductor layer can be formed.

[Brief description of drawings]

FIG. 1 is a diagram showing a method for manufacturing a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a Ga produced by a method according to an embodiment of the present invention.
It is a figure which shows the result of having observed the As layer surface with the optical microscope.

FIG. 3 is a diagram showing a result of observing the surface of a GaAs layer manufactured by a conventional method with an optical microscope.

Claims (5)

[Claims] 1. A method of manufacturing a semiconductor device for forming a III-V group compound semiconductor crystal layer on a silicon substrate, comprising: an oxide film removing step of removing an oxide film on a surface of the silicon substrate at a first temperature; At a second temperature lower than the first temperature, while introducing a group III-based gas and a group V-based gas, II on the silicon substrate
A low temperature growth film forming step of forming a low temperature growth film of an I-V group compound semiconductor; and the group III gas and the V gas at a third temperature higher than the second temperature and lower than the first temperature. A single crystal film growing step of growing a single crystal film of a III-V group compound semiconductor on the low temperature growth film while introducing a group-based gas, the oxide film removing step and the low temperature growth film forming step During the temperature decrease from the first temperature to the second temperature during the period, the introduction of the group V system gas is started from the time when a predetermined temperature lower than the first temperature and higher than the third temperature is reached. A method for manufacturing a semiconductor device, which is started. 2. The method of manufacturing a semiconductor device according to claim 1, wherein the predetermined temperature at which the introduction of the group V gas is started is about 8
A method of manufacturing a semiconductor device, wherein the temperature is lower than 00 ° C. and higher than the third temperature. 3. The method of manufacturing a semiconductor device according to claim 1, wherein the group V system gas is a group V hydride system gas. 4. The method of manufacturing a semiconductor device according to claim 1, wherein the group V gas is a group V halide gas. 5. The method of manufacturing a semiconductor device according to claim 1, wherein the group V gas is solid group V vapor.