JPH08335557A - Vapor-phase epitaxial growth apparatus - Google Patents

Abstract

PURPOSE: To sufficiently control generation of particle of epitaxial film by providing a gas distributor which assures a thermal conductivity which is equal to the specific value or less to a plurality of gas blowing ports provided to guide the reaction gas to a reaction chamber. CONSTITUTION: A vaper-phase epitaxial film is grown using a gas distributor composed of a porous quartz glass plate having the thernal conductivity of 2Wm<-1> K<-1> or less. In this case, the number of particles (particle number larger than 0.6μm<2> or more) after the growth of epitaxial film is ranged from 30 to 50 pieces/cm<2> which is less than one-half of that generated when a gas distributor made of stainless mesh is used. Thereby, the epitaxial film including less particle can be grown.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor phase epitaxial growth apparatus for semiconductor crystals.

[0002]

2. Description of the Related Art In a vapor phase epitaxial growth apparatus,
In order to grow a semiconductor epitaxial layer having a uniform composition and a large film thickness on a semiconductor substrate, it is necessary to uniformly supply the reaction gas onto the semiconductor substrate. As a method for uniformly supplying the reaction gas onto the semiconductor substrate, as shown in FIG. 3, the reaction gas is supplied to the reaction chamber 7 in which the substrate 3 is placed on the substrate holder 2 by using a plurality of gas outlets 4. There is a way to introduce.

[0003]

However, in this method, a pressure difference occurs between the place where the gas outlet 4 is provided and the place where the gas outlet 4 is not provided, so that gas winding occurs near the gas outlet 4.
Precipitates due to the reaction gas adhere to the vicinity of the gas outlet 4 and cause the generation of particles in the epitaxial film. As a method of preventing this gas winding, there is a method of providing a mesh-shaped gas distributor 6 made of metal such as stainless steel at the gas outlet 4 (FIG. 1). However, even with this method, the generation of particles in the epitaxial film could not be sufficiently suppressed.

An object of the present invention is to provide a vapor phase epitaxial growth apparatus capable of growing a vapor phase epitaxial film containing few particles.

[0005]

Means and Actions for Solving the Problems The present inventor has examined the cause of the generation of precipitates in the mesh portion. Since the metal mesh-shaped gas distributor 6 has a high thermal conductivity, it is easy to transfer heat from around the reaction tube and the temperature easily rises. Moreover, when a mesh-shaped gas distributor is attached, pressure loss occurs in the mesh portion, so that the gas convection time of the reaction gas in the mesh portion becomes long. Therefore, the temperature of the reaction gas is increased by the metal mesh-shaped gas distributor 6, and a part of the reaction gas is decomposed by the mesh-shaped gas distributor 6. Then, the decomposed deposit is the gas distributor 6
Adheres to the mesh part and falls onto the substrate during film formation, which causes particles. Therefore, in order to suppress the generation of particles, the temperature of the mesh portion of the gas distributor 6 should not be raised. That is, the present invention has been made based on the above-mentioned examination, and the thermal conductivity is 2 W in a plurality of gas outlets for introducing the reaction gas into the reaction chamber.
The vapor phase epitaxial growth apparatus is characterized by being provided with a gas distributor of m ^-1 K ^-1 or less.

In order to prevent the temperature of the mesh part from rising, the material of the gas distributor has a thermal conductivity at a temperature of 300K.
Materials of 2 Wm ^-1 K ^-1 or less are used. For example, quartz glass (thermal conductivity; 1.38 Wm ^-1 K ^-1 (temperature 300 K)), Pyrex glass
(Thermal conductivity; 1.10 Wm ^-1 K ^-1 (Temperature 300K)), Flat glass (for windows)
(Thermal conductivity; 1.3 Wm ^-1 K ^-1 (Temperature 300K)) can be used as the material of the gas distributor. If a distributor is formed using these materials, the gas can be distributed without heating the reaction gas, the decomposition deposits can be prevented from adhering to the gas distributor, and a vapor phase epitaxial film with few particles can be grown. Become. On the other hand, stainless steel (thermal conductivity; 14~17Wm ^-1 K ^-1 (temperature 300K)), iron (thermal conductivity; 80Wm ^-1 K ^-1 (temperature 300K)), alumina (thermal conductivity; 36Wm ^-1 K ^-1 (Temperature 300K), MgO (Thermal conductivity; 60W
When a material having a thermal conductivity of more than 2 Wm ^-1 K ^-1 such as m ^-1 K ^-1 (temperature 300 K)) is used, decomposition deposits adhere to the gas distributor and many particles are generated, which is preferable. Absent. Also,
The structure of the gas distributor is generally a mesh,
If it is difficult to manufacture, the same effect can be obtained by using a porous plate.

[0007]

【Example】

(Example) As an example, an InP substrate having a structure shown in FIG.
A P homoepitaxial film was grown. The structure of the reaction tube is shown in FIG. The reaction gas controlled by the flow meter 5 is
It is introduced into the reaction chamber 7 through the gas outlet 4 and the gas distributor 6. As the gas distributor 6, a gas distributor having a porous plate made of quartz glass (heat conductivity; 1.38 Wm ^-1 K ^-1 (temperature 300 K)) was used. The reaction gas is trimethylindium (TMI),
The growth conditions using phosphine (PH ₃ ) are as follows: growth temperature 650
℃, growth pressure 30 torr, H ₂ flow rate 15 l / min, PH ₃ partial pressure 0.8 torr
Is. A film forming experiment was performed three times using a gas distributor having a porous plate made of quartz glass. The number of particles after the growth of the epitaxial film was measured by counting the number of particles of 0.6 μm ² or more with a surface foreign matter inspection device using laser scattering. The results are shown in FIG. When a porous glass gas distributor made of quartz glass was used, the number of particles (the number of particles of 0.6 μm ² or more) was 30 to 50 particles / cm ² .

(Comparative Example) In the same manner as in the example, an InP homoepitaxial film of 1.0 μm was grown on an InP substrate by the metal-organic vapor phase epitaxial device having the structure shown in FIG. As the gas distributor 6, a 18-8 stainless steel (thermal conductivity; 15 Wm ^-1 K ^-1 (temperature 300 K)) porous plate gas distributor was used. Using a stainless mesh mesh gas distributor,
The results obtained when the film formation was performed three times are shown in FIG. When a stainless mesh gas distributor is used, the number of particles (the number of particles of 0.6 μm ² or more) is 70 to 100.
It was / cm ² .

When a gas distributor made of a quartz glass porous plate is used as described above, the number of particles after epitaxial film growth (the number of particles of 0.6 μm ² or more) is 30 to 50 /
It is less than half that when using a gas distributor with a cm ² and stainless steel mesh. From the above, it can be seen that a vapor phase epitaxial film with few particles can be grown by using a gas distributor made of a quartz glass porous plate having a thermal conductivity of 2 Wm ^-1 K ^-1 or less.

Further, in this embodiment, the metal-organic vapor phase epitaxial device using the gas distributor of the porous plate made of quartz glass is shown, but when the gas distributor of the porous plate made of Pyrex is used, It is also possible to use a mesh plate. Further, the same effect can be obtained when it is used in another vapor phase growth method (eg, hydride method, chloride method).

[0011]

As described above, by using the vapor phase epitaxial growth apparatus of the present invention, it is possible to grow an epitaxial film with few particles.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a vapor phase epitaxial device using a gas distributor.

FIG. 2 0.6 μm ² after growth of the epitaxial film of Example
It is a figure showing the result of having counted the number of particles above.

FIG. 3 is a diagram showing an example of a conventional vapor phase epitaxial growth apparatus.

[Explanation of symbols]

 1 Heating Device 2 Substrate Holding Table 3 Substrate 4 Gas Introducing Section 5 Flow Meter 6 Gas Distributor

Claims (1)

[Claims] 1. A vapor phase epitaxial growth apparatus comprising a gas distributor having a thermal conductivity of 2 Wm ^-1 K ^-1 or less at a plurality of gas outlets for introducing a reaction gas into a reaction chamber.