JPS62150710A - Manufacture of superlattice semiconductor - Google Patents

Abstract

PURPOSE:To enable realization of Si, Si1-xGex semiconductor superlattice which can lower the temperature of a substrate for thermal CVD and has the steep change of an interface composition by using raw materials of high order silicon hydride (SinH2n+n, n=2,3...) and GeH4. CONSTITUTION:The growth of an Si layer uses a raw material of high order silicon hydride (SinH2n+n, n=2,3...) gas, an SixGe1-x mixed crystal layer uses a raw material of the mixed gas of SinH2n+2 and germanium hydride (GeH4) and these layers are alternately and repeatedly laminated by thermal CVD. In the above-mentioned method, the thermal decomposition temperature of the high order silicon hydride, the raw material of the Si layer, is as low as 300 deg.C-500 deg.C and a single crystal thin film can be grown at a low substrate temperature of 830 deg.C-900 deg.C. This makes the composition of Si and Si1-xGex in the interface between an Si film and the Si1-xGex layer steep change and an ideal superlattice structure can be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION [(Industrial Field of Application)] The present invention relates to a method for manufacturing a Si.BizGal-x based superlattice semiconductor.

(Summary of the Invention) The present invention provides a method for manufacturing a Bi, BizCkal-z based superlattice semiconductor, in which S
The s7 layer and the BtzGel-ya layer can be grown at low substrate temperatures by alternately stacking the BizGal-z layer and the BizGal-z layer using the B-inHn+* and G-H4 mixed gas as raw materials by the CVD method. As a result, the steepness of the compositional change at the interface between the "s" and the BizCkel-1 layer is ensured, and the electro-optical characteristics are significantly improved.

(Prior art) The conventional manufacturing method of Bt, BszGel-z elementary superlattice semi-dedicated method is described in the Journal of Vacuum Science and Technology (: fourTLat of Vacuum
As can be seen in the paper published in Volume A2, page 486 of Baianca and TachnoLoly, 1984, a manufacturing method using the molecular beam evixilation method and Applied, Physics, Letters (hppLied P
OVD using monosilane (hereinafter referred to as sea number) G$H, as a raw material, as seen in the article published in vol. 41, p. 464, vol. 41, p.
There was a manufacturing method based on the law.

(Problems and objects to be solved by the invention) However, in the prior art described above, first, in the molecular beam copytaxy method, it is possible to manufacture the substrate at a low temperature;
Because it requires an ultra-high vacuum furnace and exhaust system, it takes a lot of time to obtain a high vacuum, and it is difficult to uniformly manufacture superlattice semiconductors over a large area, making it difficult to mass-produce. There are problems. In addition, although the OVD method is suitable for mass production, since it uses sea as a raw material gas, it is necessary to grow the substrate at a high temperature of 950°C to 1000°C to produce a single crystal thin film. As a result, when manufacturing superlattice semiconductors, Bt
Since the xCkel-x thin film is also grown at the same substrate temperature as SZ, a diffusion phenomenon of G atoms occurs, and the 84 layer and 5jzG
There was a problem in that the steepness of the interface between the s and -c layers was not guaranteed, and good electrical and optical properties could not be obtained.

The present invention is intended to solve these problems, and its purpose is to grow a single crystal thin film of 5iRs Sz$G#1-1 using a chemical method that can uniformly form a film over a large area. The present invention provides a method for manufacturing a superlattice semiconductor using a vapor phase growth method and at a low substrate temperature, and as a result, the composition structure of the interface between the S< layer and the 84zGg,-2 layer changes. The present invention provides a superlattice semiconductor with guaranteed steepness of change and good electrical and optical properties.

(Means for Solving the Problems) A method for manufacturing a superlattice semiconductor in which a superlattice semiconductor formed by alternately and repeatedly stacking s(,5zzG-Yo2 thin films) of the present invention is manufactured by a thermal CVD method, The growth of the layer was performed using highly hydrogenated silicon (days (?SHs+, n=298,...)
Using these two bodies as raw materials, a Si z Ge@-c mixed crystal layer is made of BtnTln-4-2 and germanium hydride (G,
It is characterized in that it is produced alternately and repeatedly by a thermal OVD method using a mixed gas of H, ) as a raw material.

(effect) According to the above manufacturing method of the present invention, it is a raw material for SZ.

% silicon hydride (SZ%mn+an=2,8
When dust, 5OTX, is used as a raw material, the thermal decomposition temperature of As a result, it has become possible to grow a single crystal thin film at a low substrate temperature of 880°C to 900°C. As a result, 84. When manufacturing S<1-zGe-based superlattice semiconductor,
Since the diffusion of the Ge element during growth, which was a problem, is within several tens of amperes, the composition of Si, Si, and -cGg changes rapidly at the interface between the a6 layer and the Sil-zGaz layer. This makes it possible to manufacture an ideal superlattice structure.

(Example) Figure 1 shows sz, sz, -cGe in an example of the present invention.
1 is a main configuration diagram of a manufacturing apparatus according to a method for manufacturing a z superlattice semiconductor. (119) was installed in a quartz thermal aVD reactor. Single crystal B (
Destroy the board. The single-crystal S (substrate is in the (100) direction of the surface, and has undergone pretreatment cleaning with a hydrofluoric acid system. (127)) The inside of the reactor is 1O
-qT.

After maintaining the vacuum in the 21 units, hydrogen gas is introduced into the reactor from the hydrogen gas cylinder (116) through the mass 70-controller (109), and at the same flow rate (D water
110) through the mass flow controller (125)
The Si of (116) is directly supplied with a rotary pump of
．． a- Release the gas cylinder Gn and move to square 70 of (107)
- Direct flow through the controller to the 125 rotary pump through the solenoid valve (101). Set the pressure inside the reaction tube to an appropriate value using the needle pulp (124),
The needle pulps (129) and (180) are used to adjust the pressure in the gas line leading to the reaction tube and the pressure in the gas line leading directly to the rotary to be the same. After this, the high frequency oscillation power supply of (121) is applied, (
120) heats the carbon susceptor in the reaction tube. The SZ, a, and gas, which were passed through the solenoid valve (101) while maintaining the substrate temperature at 880°C to 900°C, were
into the reaction tube through the L solenoid valve 102). The Eli, H, and gases introduced into the reaction tube are placed on a single crystal 84 substrate.
4. It decomposes into BinHrn, H@, and undergoes a surface reaction on the substrate surface to obtain a Si single crystal thin film. 50% Si layer
After forming a thin film of ~200A, G $ of (117)
GaT gas is introduced from the H4 gas cylinder in the same way as the 543H6 gas was introduced into the reaction tube. By using an appropriate gas mixture ratio, ai, -,
A G- mixed crystal thin film is formed. By repeating this operation many times, a superlattice semiconductor in which thin films of Bt and f3il-zGa are laminated can be obtained. Since the substrate temperature for forming this series of extremely thin films is as low as 880° C. to 900° C., the steepness of the composition at the interface is guaranteed. Figure 2 shows the G of the Si,541-cGaz interface formed in this example.
- It is a diagram showing the distribution of the concentration of elements in the film thickness direction. The measurements were performed using Auger electron spectroscopy. The solid line is s7. according to this embodiment. a.

The broken line is the conventional s4H.

This is the concentration distribution of G-element when using as the raw material.

When using a 4 H, the substrate temperature is 950° C. or higher, and diffusion of 906M molecules occurs during thin film formation.

Figure 8 shows S<,5jl-cG produced according to this example.
, is a diagram showing the atomic concentrations of s7 and G in the film thickness direction of the superlattice semiconductor 134., which has a steep interface according to the present invention.
This shows that a superlattice semiconductor of 85-zGaz has been realized.

(Effect of the invention) As described above, according to the present invention, higher-order hydrogenated silicon (
B in H, Kujutomi,? L=2,8 glue...] is made from G# ■ as raw material, the substrate temperature of thermal OVD can be lowered, and the composition change at the interface is abrupt.
It has the effect of realizing a KAZ semiconductor superlattice, which makes it possible to create semiconductors with high carrier mobility (compared to conventional A4 single crystals), high-speed switching transistors, and their integration. This enables high-speed memory and arithmetic elements. Furthermore, since the thermal 0'VD method enables uniform film formation over a large area, these devices can be manufactured in large quantities at low cost. Furthermore, at, 13t@
- Wag superlattice semiconductors have a high mobility saturation speed, so there is no deterioration in characteristics due to microfabrication, and large-scale integration is easy.

Furthermore, the Bt, Eli1-zGar:r semiconductor superlattice has potential as a light emitting element, and can provide an inexpensive and highly reliable semiconductor laser.

As described above, the manufacturing method according to the present invention has the advantage that various devices can be provided in large quantities at low cost.

[Brief explanation of drawings]

FIG. 1 is a main configuration diagram according to the superlattice semiconductor manufacturing method of the present invention. FIG. 2 shows St, 5t manufactured by the manufacturing method of the present invention.
It is a distribution map of the Ge atomic concentration in the film thickness direction at the l-zGez layer interface. FIG. 8 shows S(, B) manufactured by the manufacturing method of the present invention.
FIG. 4 is a concentration distribution diagram of each element in the film thickness direction of a 4l-zGaz superlattice semiconductor. (101) to (106), (111) to (115), (
181)00. Electromagnetic valves (107) to (110). . , Mass flow controller (116), High-order hydrogenated silicon cylinder (117)
, ,Germanium hydroxide cylinder (118), ,Hydrogen cylinder (119), ,Reactor, (120), ,High frequency coil, (121), ,High frequency power supply, (122), ,
, Ei i single crystal group [, (128), , carbon susceptor (125), (128), , rotary pump (126 N00. Waste gas treatment equipment) Applicant: Seiko Epson Corporation ,p Sheep 轡し ≧ ト made
Shiri ml each i%

Claims (1)

[Claims] Silicon single crystal (hereinafter referred to as Si) thin film and silicon germanium mixed crystal (hereinafter referred to as Si_xGe_1_-_x)
In a method for manufacturing a superlattice semiconductor in which a superlattice semiconductor formed by alternately stacking thin films is manufactured by pyrolytic chemical vapor deposition (hereinafter referred to as thermal CVD method), the growth of a Si single crystal layer is performed by high-order hydrogenation. Silicon (hereinafter referred to as Si_nH_2_n_
+_2) gas is used as a raw material, and further Si_xGe_1
A method for manufacturing a superlattice semiconductor, characterized in that ___x mixed crystal layers are alternately and repeatedly manufactured by the thermal CVD method using a mixed gas of Si_xH_2_n_+_2 and germanium hydride (hereinafter referred to as GeH_4) as raw materials.