JPS63240015A - Vapor growth method of iii-v compound semiconductor - Google Patents

Abstract

PURPOSE:To make it possible to independently generate group III raw gas containing impurity gas and group III raw gas respectively by a method wherein an impurity element, the group III raw material metal containing an impurity element and a pure group III raw material metal are provided respectively in the first and the second reaction chambers which are formed independently. CONSTITUTION:In the first reaction chamber 161 of the growing chamber containing two reaction chambers 161 and 171, the impurity element 141, to be added to the semiconductor layer in the region of the temperature higher than the temperature of a group III raw material metal 151, is arranged on the group III raw material metal 151 and the downstream side of vapor phase of the group III raw material metal 151, and a group III raw material metal 181 is arranged on the second reaction chamber 171. Then, the impurity element 141 is reacted with the group III raw material metals 151 and 181 by flowing halide gas to the first and the second reaction chambers 161 and 171 respectively, and the raw gas is supplied into a reaction tube. As a result, the unreacted halide gas which is transported without reacting with the impurity element such as Fe and the like can be prevented from reacting with a substrate 24, the flow rate of the halide gas containing the impurity element is controlled and the gas can be fed into the reaction tube in an excellent reproducible manner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vapor phase growth method for epitaxially growing a semi-insulating ■-V group compound semiconductor.

[Conventional technology]

Semi-insulating epitaxial growth layers are seen as promising and widely used as optical devices, especially current blocking layers in buried semiconductor lasers, buffer layers in high-speed field effect transistors, and electrical isolation layers in opto-electronic integrated devices. It's starting to get worse.

As a method for growing this semi-insulating semiconductor layer, the halide transport vapor phase growth method, which transports group Ⅰ elements as a halide gas, is characterized by excellent mass productivity and uniformity, and is suitable for use in regions of several μm or less. This method is suitable for forming the above-mentioned current blocking layer and separation layer because growth and buried growth are possible. Hereinafter, a method for forming an Fe-doped semi-insulating GaAs layer will be described using a specific example.

The conventional growth method for semi-insulating ■-V group compound semiconductors has been carried out using a vapor phase growth apparatus as shown in Figure 2 (
Journal Electrochemical Society (J,E
electrochem, 5oc), volume 124, 1977
, pp. 1635-1640).

In the conventional apparatus shown in FIG.
12 is placed, and a heating furnace 262 for heating the raw metal 312 and the substrate 242 is installed to cover the reaction tube 252. The generation chamber 322 in which the impurity element 142 for obtaining a semi-insulating semiconductor is placed is installed separately from the reaction tube 252, and the introduction tube 12 extending from the generation chamber 322 is installed separately from the reaction tube 252.
2 is inserted into the reaction tube 252. A heating furnace 332 that heats the generation chamber 322 is arranged separately from the heating furnace 262.

In the conventional example, a chloride vapor phase growth method in which group V elements are supplied as chloride gas is used in the halide transport method, and thereby an Fe-doped semi-insulating GaAs layer is grown. The heating furnace 262 heats G& of the raw material metal 312 placed in the reaction tube 252 and GaAs of the substrate 242 to 850° C. and 670° C., respectively. On the other hand, the generation chamber 32 provided on the upstream side of the introduction pipe 122
Fe (iron) serving as an impurity element 142 for obtaining a semi-insulating semiconductor layer is added to 2 and heated in a dedicated heating furnace 332.
The temperature is controlled within the range of 370-550°C.

When HCf is introduced into the generation chamber 322, Fe and HCJ7 react to generate solid FeCIz. Produced FeC
12 is partially converted to FeCl due to its vapor pressure at that temperature.
The two gases are introduced into the reaction tube 252 through the introduction tube 122. On the other hand, AsCl3 is supplied to the supply pipe 112. AsCl3 is heated to high temperature G! Reacts with 312,
A GaAs growth gas atmosphere is formed and introduced into reaction tube 252 .

In this way, the Fe-doped semi-insulating G
An aAs layer is grown. In this example, the resistivity is 105
A value of 1 Ω was obtained.

[Problem that the invention seeks to solve]

In the conventional vapor phase growth method for semi-insulating ■-V compound semiconductors, once the iron surface begins to be covered with the generated solid FeCl2, all the HC supplied to the generation chamber 322 is
4' will no longer be able to react with Fe, and a portion will be introduced into the reaction tube 252 unreacted. As a result, especially HC1! For example, In
When attempting to grow a semiconductor such as P, a problem arose in that the crystallinity deteriorated.

In addition, the amount of FeCl2 gas transported is determined by the set temperature.
Even if we try to control it using the vapor pressure of eCl2, the temperature in the generation chamber 322 changes slightly every time it is grown, so the amount of transport also changes greatly, making it difficult to control and reproducibly control the resistivity of the grown semiconductor layer. There was a problem with it being bad. Furthermore, the conventional method requires a dedicated heating furnace 332 for heating the impurity element, and the apparatus is also complicated.

The above problems are problems in the method of generating and transporting iron halide gas, and are not related to the method of forming the growth atmosphere for ■-V group compound semiconductors.Therefore, these problems are not discussed in the conventional example. This is not a problem specific to the chloride vapor phase growth method, but a general problem of halide transport vapor phase growth methods.

An object of the present invention is to provide a vapor phase growth method that does not require a heating furnace 332 and has excellent controllability and reproducibility for growing a high quality semi-insulating ■-■ group compound semiconductor layer. .

[Means for solving problems]

The present invention is a vapor phase growth method in which a raw material gas in a reaction tube is supplied and a semiconductor layer is laminated on a substrate placed in the reaction tube. In the first reaction chamber of the growth chamber containing the growth chamber, there is added to the semiconductor layer a temperature region higher than the temperature of the flag metal on the downstream side of the vapor phase of the flag metal. Arrange the impurity element for the first reaction, place the raw material metal in the second reaction chamber, and place the first. The method is characterized in that a halide gas is caused to flow into each of the second reaction chambers to react with the impurity element and each flag material metal, thereby supplying raw material gas into the reaction tube.

[Effect]

According to the present invention, by installing an impurity element, (1) flag material metal containing the impurity element, and (2) pure flag material metal in independent first and second reaction chambers, the impurity gas can be removed. ■ Flag fish feed gas and ■ Flag fish feed gas containing flag fish feed gas are each independently generated.

The first reason for installing the second reaction chamber is that in addition to the impurity gas generated in the first reaction chamber and the flag fish feed gas,
This is to enable flag fish feed gas to be added to growth gas. This makes it possible to freely control the electrical semi-insulating properties of the grown layer. A second chamber with a second reaction chamber installed.
The reason for this is that in addition to the impurity gas and the flag fish gas generated in the first reaction chamber, the second reaction chamber contains elements from group III, which are different from the flag fish gas generated in the first reaction chamber. This is to make it possible to add the flag fish feed gas to the growth gas. This makes it possible to obtain a multi-component mixed crystal growth layer having electrical semi-insulating properties.

The reason for arranging the raw material metal on the upstream side of the first reaction chamber and the impurity element for obtaining electrical semi-insulating property on the downstream side is as follows. ■Group halide gas generated by the reaction between the raw material metal and the halide gas comes into contact with impurity elements on the downstream side. However, since the group (III) halide gas is very stable, it does not react with impurity elements at all and is transported to the substrate as is. ■The halide gas that does not contribute to the reaction between the raw material metal and the halide gas reacts with impurity elements on the downstream side, generating impurity halide gas as a doping gas. Therefore, the Group 1 halide gas and the impurity halide gas are transported to the growth chamber. If the impurity element
When placed on the upstream side of the flag fish metal, the impurity halide gas generated upstream comes into contact with the flag fish metal on the downstream side. The impurity halide gas easily reacts with (1) the raw material metal, and (2) the impurity is taken into the raw material metal (referred to as the impurity gettering effect). As a result, the impurity halide gas is drastically reduced and is not transported onto the substrate. Therefore, it is necessary to arrange an impurity element downstream of the flag metal.

Furthermore, the reason why the temperature of the impurity element was made higher than that of the upstream fish material metal is as follows. ■The reaction efficiency of impurity elements and halide gas is lower than the reaction efficiency of flag fish metal and halide gas. In order to cause a good reaction, it is necessary to set the temperature of the impurity element high. In this method, the amount of halide gas that reaches the substrate unreacted is suppressed to a very small amount, resulting in a highly crystalline semiconductor layer that inhibits semiconductor growth.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a schematic diagram of a growth apparatus for growing an Fe-doped semi-insulating semiconductor layer used in a first embodiment of the present invention. Inside the reaction tube 251 are independent first growth chambers 1.
91 and a second growth chamber 231. The first growth chamber 191 is a chamber for growing a semi-insulating semiconductor layer, and is partitioned into a first reaction chamber 161 and a second reaction chamber 171.

In the first reaction chamber 161, I
n is placed, and Fe is placed downstream thereof as an impurity element 141. In the second reaction chamber 171, In is placed as the flag material metal 181. The second growth chamber 231 is a chamber for growing S-doped n-type tnP, and in the second growth chamber 231, In is placed as the flag material metal 221. The substrate 241 has first and second
A heating furnace 261 for heating the reaction tube 251 is installed next to the growth chamber that can be moved between the growth chambers of the reaction tube 251.
It is installed to cover 1.

Using this apparatus 6, growth was performed using a hydride vapor phase epitaxy method in which group V elements were supplied as a hydrogenation gas. HCf is used as the hydride gas, and 5 cc of HCe is connected to the supply pipe 111 in the first growth chamber 191.
/min H2 gas, HCe 5 in the supply pipe 131
t12 gas containing cc/+in, and H2 gas containing t1315 cc/min were flowed into the inlet pipe 121, respectively. In the second growth chamber 231, II□ gas containing HCJ710 cc/mtu was supplied to the supply pipe 211, and H2 gas containing PH315 cc/gin and 112S as a dopant gas was supplied to the introduction pipe 201. The heating furnace 261 heats the region of the raw material metal 151 installed in the first reaction chamber 161 at 600 degrees Celsius, the region of the impurity element 141 at 900 degrees Celsius, and the growth region where the substrate 241 is placed at 600 degrees Celsius.
It was set to 0°C and heated.

Under the above conditions, the carrier concentration is 5 x 1018C11
An Fe-doped semi-insulating InP layer was grown in the first growth chamber 191 using S-doped InP of -' as the substrate 241. Thereafter, the substrate 241 was moved to the growth chamber 231 of Section 2, and an S-doped n-type InP layer was epitaxially grown continuously on the semi-insulating InP layer.

Epitaxially grown Fe-doped semi-insulating InP
To measure the resistivity of the IJ, A o
An ohmic electrode was formed using GeNi. As a result, the resistivity of F-e Be 1 semi-insulating InP R is 1
．． It was confirmed that a high resistance semiconductor was realized. Furthermore, when similar experiments were conducted 10 times to confirm reproducibility, the variation in resistivity was as small as ±θ, 1×10 8 Ω1. Furthermore, dislocation density was measured for crystallinity evaluation. As a result, it was found that the dislocation density of the semi-insulating InP layer was as low as that of the substrate used, and the crystallinity was also good.

HC flowing into the supply pipe 111! ! Flow rate of 0.1ce/+m
When changing from in to 5 cc/win, the resistivity becomes 1
It was possible to vary the resistance from 0.02Ω1 to 108ΩΩ with good controllability.

As a second example, F
In the first reaction chamber 161 in which the e-doped semi-insulating InGaAs was grown, In is placed as the flag material metal 151, and Fe is placed downstream thereof as the impurity element 141. In the second reaction chamber 171, Ga was installed as the flag material metal 181. The second growth chamber 231 was an S-doped n-type 1nP growth chamber as in the first embodiment. In the first growth chamber 191, HCe 10 is connected to the supply pipe 111.
II2 gas containing cc/min, l in the supply pipe 131
(Ce], 2cc/m1n3 H2 gas, supply pipe 13
Add HCe 1.2cc/win to 1] 12 gas,
Further, H2 gas containing A11H310 (c/min) was flowed through the introduction pipe 121.Other growth conditions and growth methods were the same as in the first example.

The resistivity of the epitaxially grown Fe-doped InGaAs was 3.3×10′Ωcm, and it was confirmed that a high-resistance semiconductor was realized. Furthermore, the reproducibility of resistivity was also good.

In the above embodiments, a hydride vapor phase epitaxy method was used, but a chloride vapor phase epitaxy method can also be applied.

In the above embodiment, Fe is used as an impurity element,
Although IoP is used for a compound semiconductor, it is not limited to these impurity elements or compound semiconductors. Cr as an impurity element
, Co, etc., and as a compound semiconductor, GaAs
, Gal', etc. may also be used.

〔Effect of the invention〕

As described above, if the vapor phase growth method according to the present invention is used, F
Since unreacted halide gas, which is transported without reacting with impurity elements such as e, can be prevented from reaching the substrate, deterioration in the quality of the semi-insulating semiconductor layer can be prevented. Further, the flow rate of halide gas containing impurity elements can be controlled and supplied into the reaction tube with good reproducibility, and as a result, growth with excellent controllability and reproducibility of electrical semi-insulating properties can be achieved. moreover,
A dedicated heating furnace for heating impurity elements is also not required.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a vapor phase growth apparatus used in an embodiment of the present invention, and FIG. 2 is a schematic diagram of a conventional example. 111.131,211... Supply pipe, 121°201
and 122... introduction pipe, 141 and 142...
Impurity element, 151, 181, 221, 312...■
Flag fish metal, 161...first reaction chamber, 171...
Second reaction chamber, 191...First growth chamber, 231...
- Second growth chamber, 241, 242...substrate, 251.
252...Reaction tube, 261,262.332...Heating furnace, 322...Generation chamber. Agent Patent Attorney Uchihara Oto No. 1 ttt, 131. 211- ・Combined business 721.20
1.-Suga

Claims (1)

[Claims] In a vapor phase growth method in which a raw material gas in a reaction tube is supplied and a semiconductor layer is laminated on a substrate placed in the reaction tube,
A reaction tube containing a plurality of growth chambers is prepared, and a group III source metal is placed in the first reaction chamber of the growth chamber containing two reaction chambers, and a group III source metal is placed on the downstream side of the gas phase of the group III source metal. arranges an impurity element, sets the temperature of the region where the impurity element is arranged higher than the temperature of the region where the group III raw material metal is arranged, and further arranges the group III raw material metal in the second reaction chamber, A III-V group characterized in that a halide gas is caused to flow through each of the first and second reaction chambers to react with the impurity element and each group III raw material metal, and the raw material gas is supplied into the reaction tube. A method for vapor phase growth of compound semiconductors.