JPH0620974A - Vapor phase growing method - Google Patents

Abstract

PURPOSE:To enhance uniformity within the surface in doping by a method wherein a mixture ratio of doping material gas composed of Si2H6 and SiH4 is adjusted so that a dissolving speed in its growing temperature may coincide with that of III group material gas. CONSTITUTION:Carrier, gas is used as H2 and trimethylindium, triethylgallium, phosphine, SiH4, and Si2H6 are used as material gas, and they are respectively introduced from a material introducing inlet 1, and high frequency coils 5 are electrically connected, and a reaction pipe 2 is heated, so that an N type InGaP layer lattice-coordinating a GaAs substrate 4 may grow. Here, a gas concentration ratio of SiH4 to Si2H6 is decided so as to coincide with a dissolving speed in a growing temperature of III group material gas. As a result, uniformity within the surface in carrier concentration becomes 2% or less on a 3-inch substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor phase growth method for III-V compound semiconductor crystals.

[0002]

2. Description of the Related Art In the metal-organic vapor phase epitaxy method (MOVPE method) used for manufacturing optical devices and high-speed devices, crystals having good characteristics can be grown over a large area, and active research and development is proceeding. Has been.

In recent years, the analysis of the carrier gas flow in the reaction tube has been advanced by simulation (Journal of Crystal Growth (Journal of Crystal Growth)).
Crystal Growth), Volume 100, 5
(See page 45), good crystal characteristics have come to be obtained not only under reduced pressure growth but also under normal pressure growth (Journal of Applied Physics (Journ).
al of Applied Physics, Vol. 67, No. 12, p. 7578).

[0004]

The general lateral reaction tube shown in FIG. 1 is used to use Si as an n-type dopant III-
When vapor-phase growth of a group V compound semiconductor is performed, the decomposition rate of the dopant gas at the crystal growth temperature is significantly different from the decomposition rate of the group III source gas, and thus the uniformity of the doping concentration is reduced in the plane of the crystal substrate. There is.

An object of the present invention is to solve this problem and to provide a vapor phase growth method of a III-V group compound semiconductor excellent in in-plane uniformity of doping.

[0006]

In order to achieve the above object, in the vapor phase growth method according to the present invention, when a III-V group compound semiconductor crystal containing Si as an n-type dopant is grown, a doping source gas is used. Si ₂ H ₆ and SiH
By using the mixed gas of ₄ and adjusting the mixing ratio, the decomposition rate at the growth temperature of the doping source gas is made to match the decomposition rate of the group III source gas.

[0007]

[Action] The Si using a horizontal reaction tube shown in FIG. 1 when performing a group III-V compound semiconductor vapor phase growth of an n-type dopant, when using SiH ₄ as a raw material gas of Si, the substrate plane The doping concentration decreases on the upstream side of.
It is considered that this is because the decomposition rate of the SiH ₄ gas at the crystal growth temperature is slower than that of the group III source gas that determines the growth rate.

On the other hand, when Si ₂ H ₆ is used as the Si source gas, the doping concentration decreases on the downstream side of the substrate surface. It is considered that this is because the decomposition rate of the Si ₂ H ₆ gas at the crystal growth temperature is higher than that of the group III source gas that determines the growth rate, so that the source gas is depleted and the concentration decreases.

Therefore, in the present invention, S which has a high raw material decomposition rate
The i ₂ H ₆ gas and the SiH ₄ gas having a slow starting material decomposition rate are mixed, and the mixing ratio is adjusted to match the starting material decomposition rate at the growth temperature of the group III source gas to determine the growth rate. To improve the uniformity of the doping concentration.

[0010]

Embodiment An embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows a block diagram of an apparatus used in the vapor phase growth method according to the present invention. In FIG. 1, a quartz reaction tube 2 having a raw material inlet 1 at one end and having a high frequency coil 5 installed on the circumference thereof.
A carbon susceptor 3 is placed on the central wall of the, and a 3-inch GaAs substrate 4 is mounted thereon.

From the raw material inlet 1, the carrier gas is set to H ₂ and trimelotylindium (TMI), triethylgallium (TEG), phosphine (PH ₃ ), silane (S) are used.
iH ₄ ) and disilane (Si ₂ H ₆ ) are introduced as source gases, respectively, and the high frequency coil 5 is energized to heat the reaction tube 2 to grow an n-type InGaP layer lattice-matched to the GaAs substrate 4.

Here, the source gas concentration ratio of SiH ₄ and Si ₂ H ₆ was determined so as to match the decomposition rate at the growth temperature of the group III source gas. Reaction tube pressure 760To
rr and the carrier gas flow rate is 10 SLM each and n
A type InGaP layer was grown. As a result, in-plane uniformity of carrier concentration on the 3-inch substrate was achieved to 2% or less.

On the other hand, as a result of performing similar growth using only SiH ₄ gas as a doping material gas, the carrier concentration on the downstream side was high on the 3-inch substrate, and the in-plane uniformity was about 10%. Moreover, as a result of performing similar growth using only Si ₂ H ₆ gas as a doping source gas, the carrier concentration on the upstream side was high on the 3-inch substrate, and the in-plane uniformity was about 15%.

[0014]

As described above, according to the present invention, Si ₂ H ₆ and SiH ₄ are used as doping source gases in a vapor phase growth method for growing a III-V group compound semiconductor crystal using Si as an n-type dopant. The use of a mixed gas of and has an effect of enabling crystal growth with high in-plane uniformity of carrier concentration.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of a vapor phase growth method according to the present invention.

[Explanation of symbols]

 1 Raw material inlet 2 Quartz reaction tube 3 Carbon susceptor 4 GaAs substrate 5 High frequency coil

Claims (1)

[Claims] 1. III-V using Si as an n-type dopant
In a vapor phase growth method for growing a group compound semiconductor crystal,
It is characterized in that a mixed gas of Si ₂ H ₆ and SiH ₄ is used as a doping raw material gas, and the mixing ratio is adjusted so that the decomposition rate at the growth temperature of the doping raw material gas matches the decomposition rate of the group III raw material gas. Vapor growth method.