JPH06244109A - Vapor growth method of compound semiconductor - Google Patents

Abstract

PURPOSE:To grow an epitaxial layer uniform in thickness all over the whole surface of an epitaxial wafer wherein edge growth is not generated, in relation to the vapor growth of compound semiconductor. CONSTITUTION:A cylindrical upper reaction chamber 110 and a cylindrical lower reaction chamber 111 in which substrates 105 for epitaxial growth are so placed as to face each other in a reaction tube 102, at the time of epitaxial growth. Etching gas is supplied from etching gas feeding tubes 112 arranged around material gas feeding ports of the upper reaction chamber 110 and the lower reaction chamber 111. The growth is progressed while the gas is supplied.

Description

Detailed Description of the Invention

[0001]

This invention relates to compound semiconductors such as G
The present invention relates to a vapor phase growth method for a Group 3-5 compound semiconductor such as aAs, InP, InGaAs.

[0002]

2. Description of the Related Art In recent years, there has been a rapid increase in demand for long-wavelength band light-receiving devices using compound semiconductors, such as avalanche photodiodes and PIN photodiodes. Avalanche photodiodes and PIN photodiodes are formed in a heteroepitaxial layer having a multi-layer structure grown on an n ⁺ -InP substrate, and in order to grow this epitaxial layer, generally, a vapor phase growth method by a hydride method is used. Is used.

FIG. 4 shows a vapor phase growth apparatus used for vapor phase growth by a conventional hydride method. In FIG. 4, 401 is a growth reactor, 402 is a reaction tube, 403 is a Group 3 source material,
404 is a substrate holder, 405 is a substrate, 406 is a Group 3 raw material transport gas supply pipe, 407 is a 5 raw material group gas supply pipe, 40
8 is a doping gas supply pipe, 409 is a gas diffuser, 410 is an upper reaction chamber, and 411 is a lower reaction chamber.

According to this method, a Group 3 source material 40 placed in a high temperature region in a reaction chamber 402 heated by a growth furnace 401 is used.
3. For example, on Ga or In, HCl gas, which is a Group 3 source material transport gas, is supplied from a Group 3 source material transport gas supply pipe 406 to react with a solid Group 3 source material, and this reaction product gas is used as a Group 3 source material gas. Further, a hydride of a Group 5 raw material component, for example, AsH ₃ or PH ₃ is supplied from the Group 5 raw material gas supply pipe 407 to obtain a Group 5 raw material gas, which is thoroughly mixed and stirred through a gas diffuser 409 in which several perforated plates are combined. After that, the substrate holder 404 placed in the low temperature region in the reaction tube 402
It is transported to the upper substrate 405 and reacted there to grow an epitaxial layer having a desired composition.

The substrate holder 404 is a reaction tube 402.
Since it can rotate in the reaction tube and can be positioned in front of the upper reaction chamber 410 and the lower reaction chamber 411 in the reaction tube, for example, Ga as a Group 3 raw material and AsH ₃ as a Group 5 raw material gas in the upper reaction chamber 410 are used. In the lower reaction chamber 411, In is used as a Group ₃ source material and PH ₃ is used as a Group 5 source material gas.
5 is positioned in front of the lower reaction chamber 411 to grow an InP layer, and then the substrate 405 is moved in front of the upper reaction chamber 410.
By growing the nGaAs layer, InGaAs / I
It is possible to grow an nP heteroepitaxial layer.

When the n-type epitaxial layer is grown, if necessary, Si is added from the doping gas supply pipe 408.
An n-type dopant such as S or S is supplied to grow an epitaxial layer.

In order to grow the epitaxial layer thickness and carrier concentration uniformly on the substrate 405 by this growth method, it is necessary to supply the source gas evenly on the substrate. Therefore, conventionally, the substrate 405 has been arranged to face the center of the upper or lower reaction chamber as much as possible, and the source gas is evenly supplied onto the substrate to grow the film.

[0008]

However, even if the source gas is evenly supplied to the substrate by locating the substrate in the center of the upper or lower reaction chamber as much as possible, the peripheral portion of the substrate is always compared with the central portion of the substrate. Since the consumption of the film on the substrate is small, that is, the high-concentration raw material gas is flowing, the growth rate of the epitaxial layer increases and the layer thickness increases in the outermost peripheral portion of the substrate. Therefore, there is a problem that the epitaxial layer thickness varies greatly, and a uniform epitaxial layer having a variation (average of σ / x) of 6% or less cannot be obtained.

FIG. 5 shows a wafer in-plane distribution of the total epitaxial layer thickness when the InGaAs / InP heteroepitaxial layer is grown on the InP substrate by the conventional method. As shown in FIG. 5, in the epitaxial layer growth on the 50 mmφ substrate, the variation was 6.3%, and it can be seen that the layer thickness becomes thicker at the outermost periphery of the substrate.

An object of the present invention is to eliminate the above-mentioned inconvenience, and to provide a vapor phase growth method of a compound semiconductor having a good epitaxial layer thickness uniformity in a wafer surface.

[0011]

According to the vapor phase growth method of a compound semiconductor of the present invention, a source gas is sent from one end of a cylindrical reaction chamber provided in a reaction tube, and the source gas flows to the other end of the reaction chamber. In the vapor phase growth method of a compound semiconductor in which an epitaxial layer is formed on the surface of a crystal substrate held so as to be orthogonal to the etching substrate, an etching gas is supplied from the peripheral portion of the other end of the reaction chamber.

[0012]

The present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a vapor phase growth apparatus for explaining a first embodiment of the present invention.

In FIG. 1, 101 is a growth furnace, 102 is a reaction tube, 103 is a Group 3 source material, 104 is a substrate holder, and 1 is a substrate holder.
Reference numeral 05 is a substrate, 106 is a Group 3 raw material transport gas supply pipe, 107
Is a group 5 source gas supply pipe, 108 is a doping gas supply pipe, 109 is a gas diffuser, 110 is a cylindrical upper reaction chamber, 111 is a cylindrical lower reaction chamber, and 112 is an etching gas supply pipe.

The reaction chamber 102 is inserted into the growth furnace 101 and heated by a heater. In the high temperature region of about 900 ° C. in the reaction tube 102, G
a 400 g, In 800 g, and I in the lower reaction chamber 111.
n800g is installed. Next, the substrate holder 104 is rotated to position the substrate 105 on the substrate holder 104 in front of the lower reaction chamber 111 so that the substrate 105 faces the flow of the source gas at a right angle. Group 3 raw material transport gas supply pipe 1
From 06, 100% of 10% HCl which is a group 3 raw material transport gas is used.
Supply ml / min. On the other hand, Group 5 source gas supply pipe 107
150m of 10% PH ₃ which is a hydride of Group 5 component
l / min supply.

Further, 10% HCl, which is an etching gas, is supplied at 30 ml / min from an etching gas supply pipe 112 provided around the upper reaction chamber 110. InP grown by growth in the lower reaction chamber by the above operation
An InGaAs layer is epitaxially grown on the layer.

FIG. 2 is a wafer in-plane distribution diagram of the total epitaxial layer thickness when the InGaAs / InP heteroepitaxial layer is grown on the InP substrate by the vapor phase growth method according to this embodiment. As shown in FIG. 2, in the growth method according to the present embodiment, the variation σ / x in the epitaxial growth on the substrate of 50 mmφ was 2.4%, which was uniformed to about 1/3 of the conventional variation.

In the first embodiment, when epitaxial growth is performed, an etching gas is supplied at the same time as supplying the group 3 and group 5 source gases necessary for growth to make the epitaxial layer thickness uniform. But first 3
Similar effects can be obtained when the epitaxial layers are made uniform by supplying the group III and group 5 source gases to perform the epitaxial growth and then supplying the etching gas to perform the gas etching of the epitaxial layers. The second embodiment will be described below.

An InP layer is epitaxially grown in the lower reaction chamber 111 under the same method and conditions as in the first embodiment.
However, the etching gas is not supplied. After the growth of the InP layer, the etching gas supply pipe 112 in the lower reaction chamber 111 supplies 10% HCl as an etching gas to 30 ml / mi.
n is supplied and gas etching is performed to homogenize the epitaxial layer.

Next, by the same method and conditions as in the first embodiment,
An InGaAs layer is epitaxially grown in the upper reaction chamber 110. Also in this case, the etching gas is not supplied. After the growth of the InGaAs layer, etching gas 10% HCl is supplied from the etching gas supply pipe 112 of the upper reaction chamber 110.
Of 30 ml / min to perform gas etching to homogenize the epitaxial layer.

FIG. 3 shows the in-plane distribution of the total epitaxial layer thickness when the InGaAs / InP heteroepitaxial layer is grown on the InP substrate according to the second embodiment.

As shown in FIG. 3, in the growth according to the second embodiment, the variation (average of σ / x) in epitaxial growth on a substrate of 50 mmφ is 2.0%, which is almost the same effect as in the first embodiment. It turns out that In the second embodiment, gas etching is performed after growth of the epitaxial layer, so that an unstable layer such as composition due to gas switching immediately after growth of the epitaxial layer is etched off to obtain a steep profile in the growth direction of the epitaxial layer. Can be done.

[0022]

According to the present invention, the vapor-phase growth of a Group 3-5 compound semiconductor is performed by the method described above, and etching gas is supplied from the peripheral portion of the reaction chamber facing the epitaxial growth substrate in the crystal growth reaction chamber. By supplying the raw material gas in the peripheral portion of the substrate is less consumed by the epitaxial growth than in the central portion of the substrate, that is, a phenomenon in which the epitaxial growth rate at the outermost peripheral portion of the substrate is increased due to the flow of the raw material gas having a high concentration, Alternatively, by performing gas etching having a high etching rate at the outermost peripheral portion of the substrate, it is possible to achieve uniform growth of the epitaxial layer thickness within the wafer surface.

[Brief description of drawings]

FIG. 1 is a sectional view of a vapor phase growth apparatus for explaining a first embodiment of the present invention.

FIG. 2 is a diagram showing a wafer in-plane distribution of a total epitaxial layer thickness when a heteroepitaxial layer is vapor-grown according to the first embodiment.

FIG. 3 is a view showing the in-plane distribution of the total epitaxial layer thickness when a heteroepitaxial layer is vapor-phase grown according to the second embodiment.

FIG. 4 is a sectional view of a vapor phase growth apparatus for explaining a conventional vapor phase growth method.

FIG. 5 is a diagram showing a wafer in-plane distribution of the total epitaxial layer thickness when a heteroepitaxial layer is vapor-phase grown by a conventional method.

[Explanation of symbols]

 101, 401 Growth reactor 102, 402 Reaction tube 103, 403 Group 3 source material 104, 404 Substrate holder 105, 405 Substrate 106, 406 Group 3 source material transport gas supply tube 107, 407 Group 5 source material transport gas supply tube 108, 408 Doping gas Supply pipe 109,409 Gas diffuser 110,410 Upper reaction chamber 111,411 Lower reaction chamber 112 Etching gas supply pipe

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] October 19, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

The reaction tube 102 is inserted into the growth furnace 101 and heated by a heater. In the high temperature region of about 900 ° C. in the reaction tube 102, G
a 400 g, In 800 g, and I in the lower reaction chamber 111.
n800g is installed. Next, the substrate holder 104 is rotated to position the substrate 105 on the substrate holder 104 in front of the lower reaction chamber 111 so that the substrate 105 faces the flow of the source gas at a right angle. Group 3 raw material transport gas supply pipe 1
From 06, 100% of 10% HC1 which is a Group 3 raw material transport gas
Supply ml / min. On the other hand, Group 5 source gas supply pipe 107
150m of 10% PH ₃ which is a hydride of Group 5 component
l / min supply.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

Further, 10% HCl, which is an etching gas, is supplied at 30 ml / min from an etching gas supply pipe 112 provided around the lower reaction chamber 111. By the above operation, an InP epitaxial layer is grown on the substrate 105 on the substrate holder 104 placed in a low temperature region of about 670 ° C.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

Next, the substrate holder 104 is rotated to position the substrate 105 on the substrate holder 104 in front of the upper reaction chamber 110 so that the substrate 105 faces the flow of the source gas at a right angle. From the Group 3 raw material transport gas supply pipe 106, 100 ml / min of 10% HCl which is the Group 3 raw material transport gas
Supply. On the other hand, AsH ₃ which is a hydride of a Group 5 component is supplied from the Group 5 source gas supply pipe 107 at 50 ml / min.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

Further, 10% HCl, which is an etching gas, is supplied at 30 ml / min from an etching gas supply pipe 112 provided around the upper reaction chamber 110. InP grown by growth in the lower reaction chamber by the above operation
An InGaAs layer is epitaxially grown on the layer.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

FIG. 2 is a wafer in-plane distribution diagram of the total epitaxial layer thickness when an InGaAs / InP heteroepitaxial layer is grown on an InP substrate by the vapor phase growth method according to this embodiment. As shown in FIG. 2, in the growth method according to the present embodiment, the variation σ / x in the epitaxial growth on the substrate of 50 mmφ was 2.4%, which was uniformed to about 1/3 of the conventional variation.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction content]

In the first embodiment, when epitaxial growth is performed, the etching gas is supplied at the same time as supplying the group 3 and group 5 source gases necessary for growth to make the epitaxial layer thickness uniform. But first 3
Similar effects can be obtained when the epitaxial layers are made uniform by supplying the group III and group 5 source gases to perform the epitaxial growth and then supplying the etching gas to perform the gas etching of the epitaxial layers. The second embodiment will be described below.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

An InP layer is epitaxially grown in the lower reaction chamber 111 under the same method and conditions as in the first embodiment.
However, the etching gas is not supplied. After the growth of the InP layer, the etching gas supply pipe 112 in the lower reaction chamber 111 supplies 10% HCl as an etching gas to 30 ml / mi.
n is supplied and gas etching is performed to homogenize the epitaxial layer.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

Next, with the same method and conditions as in the first embodiment,
An InGaAs layer is epitaxially grown in the upper reaction chamber 110. Also in this case, the etching gas is not supplied. After the growth of the InGaAs layer, etching gas 10% HCl is supplied from the etching gas supply pipe 112 of the upper reaction chamber 110.
Of 30 ml / min to perform gas etching to homogenize the epitaxial layer.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

FIG. 3 shows a wafer in-plane distribution of the total epitaxial layer thickness when an InGaAs / InP heteroepitaxial layer is grown on an InP substrate according to the second embodiment.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

As shown in FIG. 3, in the growth according to the second embodiment, the variation (average of σ / x) in epitaxial growth on a substrate of 50 mmφ is 2.0%, which is almost the same effect as that of the first embodiment. It turns out that In the second embodiment, gas etching is performed after growth of the epitaxial layer, so that an unstable layer such as composition due to gas switching immediately after growth of the epitaxial layer is etched off to obtain a steep profile in the growth direction of the epitaxial layer. Can be done.

[Procedure Amendment 11]

[Document name to be amended] Statement

[Name of item to be corrected] 0024

[Correction method] Change

[Correction content]

[0024]

According to the present invention, the vapor-phase growth of a Group 3-5 compound semiconductor is performed by the above-described method, and etching gas is supplied from the peripheral portion of the reaction chamber for facing the epitaxial growth container plate in the reaction chamber for crystal growth. By supplying the raw material gas in the peripheral portion of the substrate is less consumed by the epitaxial growth than in the central portion of the substrate, that is, a phenomenon in which the epitaxial growth rate at the outermost peripheral portion of the substrate is increased due to the flow of the raw material gas having a high concentration, Alternatively, by performing gas etching having a high etching rate at the outermost peripheral portion of the substrate, it is possible to achieve uniform growth of the epitaxial layer thickness within the wafer surface.

Claims (1)

[Claims] 1. A surface of a crystal substrate which is fed with a raw material gas from one end of a cylindrical reaction chamber provided in a reaction tube and is held at the other end of the reaction chamber so as to face the flow of the raw material gas at right angles. In the vapor phase growth method of a compound semiconductor for forming an epitaxial layer, an etching gas is supplied from a peripheral portion of the other end of the reaction chamber.