JPH01310532A - Metal organic vapor phase epitaxial growth system - Google Patents

Abstract

PURPOSE:To make it possible to form a uniform and stable epitaxial layer by a method wherein the ceiling wall of a chamber is positioned close to the surface of a crystal substrate as much as possible in order to revert the turbulence of raw gas caused by a heat convection, and an exhaust hole is provided on the upper part so that the heated raw gas used to grow the epitaxial layer can be easily discharged. CONSTITUTION:A plurality of nozzles 9, provided with a flow-rate controller 10 which is aligned and arranged corresponding to the size of the crystal substrate 5 and facing the substrate 5, are provided on the position close to the surface of the crystal substrate 5 in parallel with it. Exhaust means 15b, which sucks the raw gas 7, jetted out from each nozzle 1, at least in upward direction, are provided on both sides of the alignment direction of the nozzles 9 leaving an almost equal interval. Accordingly, the raw gas 7 which contributes the growth of the epitaxial layer, becomes the controlled raw gas 7 jetting out from the nozzle 9. As a result, a stable and uniform epitaxial layer can be formed.

Description

[Detailed Description of the Invention] [(Already required)] This invention relates to an organometallic vapor phase epitaxy apparatus for manufacturing semiconductor devices by a vapor phase epitaxy method, and the purpose is to efficiently form a uniform epitaxial layer on a crystal substrate. An organometallic vapor phase growth apparatus for growing an epitaxial layer in a vapor phase on a surface of a crystal substrate by spraying raw material gas ejected from a plurality of nozzles onto a heated crystal substrate that rotates in a plane, the device comprising: A plurality of nozzles equipped with flow rate adjusting parts facing the crystal substrate and arranged in alignment corresponding to the size of the crystal substrate, on the ceiling wall portion of the chamber having the ceiling wall in a position parallel to and close to the crystal substrate; Exhaust means for sucking at least upwardly the raw material gas ejected from each nozzle is provided at positions substantially equally spaced on both sides parallel to the alignment direction of the plurality of nozzles.

(Industrial Application Field) The present invention relates to an apparatus for manufacturing semiconductor devices using a vapor phase growth method, and more particularly, to an organometallic vapor phase method for efficiently forming a uniform epitaxial layer on a crystal substrate to improve productivity. Regarding growth equipment.

When forming an organic metal epitaxial layer on a heated crystal substrate in a chamber by spraying a gaseous body containing raw material components (hereinafter referred to as raw material gas) on the substrate, the raw material components diffuse into the crystal layer on the substrate. The amount depends largely on the flow rate of the source gas flowing over the substrate.

Therefore, in order to form a uniform epitaxial layer over the entire surface of the substrate, it is necessary to spray the raw material gas in a uniform amount and with a uniform flow velocity distribution over the entire surface.

(Prior art) No. 2M is a diagram explaining an example of a conventional vapor phase growth apparatus, (8) shows the overall configuration diagram, and B) and (C) are enlarged views of the main parts showing the flow of gas. FIG.

Moreover, FIG. 3 is a diagram showing the actual flow of raw material gas.

In FIG. 2 (8), the chamber 1 is equipped with a rotating shaft 2 that is connected to an external rotating mechanism (not shown) and rotates, for example, in the direction R shown in the drawing, and the upper flange surface 2 of the rotating shaft 2
A susceptor 4 made of carbon and heated by a coil 3 provided outside the chamber 1 is fixed to a.

Further, the crystal substrate 5 to be processed, on which an epitaxial layer is formed on the surface (upper surface in the figure), is placed with its center aligned with the rotation center of the susceptor 4.

On the other hand, the raw material gas 7 sent out from the gas supply system 6 is supplied to a pipe 8
After passing through the chamber, the raw material gas 7 is ejected onto the surface of the crystal substrate 5 from a plurality of nozzles 9 installed near the holes for the chamber. Since an epitaxial layer can be obtained, a flow rate adjustment section indicated by 10 is provided in front of nozzle 9 for each nozzle. ffi'l can be adjusted.

Reference numeral 11 in the figure is an exhaust pump for discharging the raw material gas 7 after the reaction force has been applied to the surface of the crystal substrate 5 for 9 hours.

Here, the pressure inside the chamber 1 is reduced to about 0.1 atm, the crystal substrate 5 is heated to around 650°C by the susceptor 4, and the rotating shaft 2 is rotated at about 60 rpm. ), triethyl gallium (
TEG), hydrogen gas H using arsine (ASH3) as raw material
2 as a carrier is blown onto the surface of the crystal substrate 5 at a flow rate of 2 to 3 m/sec as shown in the figure.
For example, an epitaxial layer of indium, gallium, and arsenic (1 nGaAs) is formed to have a uniform thickness.

In the enlarged view (B) of the nozzle 9, the nozzle 9 is composed of four nozzles 9a, 9b, 9c, and 9d aligned in a line, and these four aligned nozzles are diametrically aligned. The crystal substrate 5 is arranged at a position parallel to the nozzle and approximately 10 to 20 mm away from the raw material gas ejection port of the nozzle.

When raw material gas is jetted from each nozzle in this state, for example, raw material gas 7b jetted from nozzles 9h and 9c;
7c is thermally decomposed near the surface of the crystal substrate 5, and as shown in the figure.
, ■ Proceed in two directions.

On the other hand, raw material gases 7a and 7d ejected from nozzles 9a and 9d on both sides proceed in three directions (1), (2), and (2) as shown in the figure.

Therefore, the flow rate of the nozzles 9a and 9d at both ends is increased compared to the nozzles 9b and 9c located in the center (for example, about 1.3
This makes it possible to form a uniform epitaxial layer.

That is, in the diagram (C) showing the film thickness distribution of the source gas when the crystal substrate 5 is not rotated, the X direction corresponds to the X direction in Figure (B), and the Y direction corresponds to the Y direction in Figure (B). Compatible.

In this case, the film thickness distribution in the X direction is such that the gas flow rate from the nozzles located at both ends is larger than that at the central part explained in Figure (B), so the distribution curve C is as shown in c', c”
Two mountains are formed.

On the other hand, the film thickness distribution in the Y direction will form a distribution curve CI with the maximum peak on the X-ray where the gas is blown.

Here, the crystal substrate 5 is rotated as described above, and a gas layer exhibiting a temporally averaged film thickness distribution is applied to the crystal substrate 5.
Formation of a uniform epitaxial layer thereon can be achieved.

However, in a vapor phase growth apparatus having such a configuration, the chamber 1
The shape of the susceptor 4 on which the crystal substrate 5 is placed is the source gas 7.
Due to reasons such as higher temperature, convection occurs in the flow of the raw material gas 7, and the above-mentioned ideal state is not necessarily achieved.

Figure 3, which shows the actual flow of raw material gas, is the diagram in Figure 2 (B
) and (C) are cut in the Y direction. For example, the raw material gas 7 ejected from the nozzle 9 is shown in Figure 2 (
As explained in B), after being sprayed onto the surface of the crystal substrate 5, it separates into two directions, ``■'' and ``■''. The raw material gas 7 is heated and rises while traveling along the chamber 1, and after colliding with the ceiling wall 1a of the chamber 1, the material gas 7 descends in the direction of 2 and is discharged to the outside from the exhaust pump 11.

At this time, the shaded areas A and PI become convection areas that follow the flow of the raw material gas 7 and disturb the flow of the raw material gas 7.

Therefore, the supply of source gas 5 near the surface of crystal substrate 5, which contributes to the formation of the epitaxial layer, often fluctuates due to unexpected influences.

Furthermore, the contamination of the inner wall of the semiconductor layer 1 due to the flow of the raw material gas 7 caused by convection inhibits the formation of an epitaxial layer with excellent characteristics.

[Problem to be solved by the invention]

A conventional vapor phase growth apparatus has a problem in that it is not possible to form a uniform and stable epitaxial layer on a crystal substrate.

[Means to solve the problem]

The above-mentioned problem lies in the metal-organic vapor phase epitaxy apparatus, which sprays raw material gas ejected from multiple nozzles onto a heated crystal substrate rotating in the same plane to grow an epitaxial layer on the surface of the crystal substrate in a vapor phase. A chamber having a ceiling wall located parallel to and close to the crystal substrate surface is provided with a flow rate adjusting section facing the crystal substrate and aligned in accordance with the size of the crystal substrate. A metal organic vapor phase growth apparatus comprising a plurality of nozzles, and an exhaust means for sucking at least upwardly the raw material gas ejected from each of the nozzles, at positions substantially equally spaced on both sides parallel to the alignment direction of the plurality of nozzles. solved by.

(Function) In order to always form a stable and uniform epitaxial layer on a crystal substrate, it is necessary to suppress the convection that occurs in the flow of the source gas and to remove the source gas that has contributed to the growth of the epitaxial layer as quickly as possible. is necessary.

In the vapor phase growth apparatus of the present invention, the ceiling wall of the chamber 1 is placed as close as possible to the surface of the crystal substrate in order to prevent disturbance of the raw material gas due to thermal convection, and the heated raw material that has finished contributing to the growth of the epitaxial layer is placed as close as possible to the surface of the crystal substrate. It is configured with an exhaust hole that exhausts the gas upward so that it can be easily exhausted.

Therefore, the raw material gas that contributes to the growth of the epitaxial layer is
Since only controlled raw material gas is ejected from the nozzle, it is possible to form an epitaxial layer with stable and uniform characteristics.

[Example] FIG. 1 is a diagram showing an example of the configuration of a vapor phase growth apparatus according to the present invention, in which (8) represents a front view and (B) represents a side view.

In Figure (8), a rotating shaft 16 is attached to the chamber 15, which is connected to an external rotating mechanism (not shown) and freely rotates, for example, in the direction R shown in the figure. Carbon 16a is heated by the coil 3 provided along the outer wall of the chamber 15.
A susceptor 17 made of the following is fixed.

Further, as in the case of FIG. 2, the crystal substrate 5 on which the epitaxial layer is formed on the surface (upper surface in the figure) is placed so that its center coincides with the rotation center of the susceptor 17.

On the other hand, the raw material gas 7 sent out from the gas supply system 6 is supplied to a pipe 8
After passing through the chamber 15, the liquid is ejected onto the surface of the crystal substrate 5 from a plurality of nozzles 9 arranged in a line similar to the nozzles 9 shown in FIG. 2, which are installed near the top of the chamber 15.

The second point is that a flow rate adjustment section 10 for changing the flow rate of the raw material gas 7 is provided between each nozzle and the pipe 8.
This is the same as the case shown in the figure.

In addition, in the side cross-sectional view (B) when the above-mentioned figure (A) is viewed from the F direction, the plurality of nozzles 9 of the chamber 15 are arranged substantially parallel to each other in a row, and are configured so that exhaust air is discharged to the upper part of the chamber 15. An exhaust hole 15b is formed, and the exhaust hole 15b is connected to the exhaust pump 11 installed outside the chamber.
is connected to.

In the vapor phase growth apparatus having such a configuration, the raw material gas 7 controlled for each nozzle by the flow rate controller 10 is ejected from each nozzle and collides with the crystal substrate 5, and then splits into both sides and flows into the ceiling wall 15+F of the chamber 15. The air flows through the gap shown in the figure (3), is sucked upward by the exhaust hole 15b, and is further exhausted to the outside from the exhaust pump 11.

In this case, convection areas such as the A and B 8U regions explained in FIG. 3 do not occur and the flow of the raw material gas 7 is not disturbed, so the raw material gas 7
By supplying the raw material to the crystal substrate 5 by spouting,
A uniform and characteristically stable epitaxial layer can be formed on the crystal substrate 5.

〔Effect of the invention〕

According to the present invention, it is possible to provide a continuous metal vapor phase growth apparatus capable of forming a uniform and characteristically stable epitaxial layer on a crystal substrate.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a configuration example of a vapor phase growth apparatus according to the present invention, FIG. 2 is a diagram explaining an example of a conventional vapor phase growth apparatus, and FIG. 3 is a diagram showing an actual flow of raw material gas. It is. In the figure, 3 is a coil, 5 is a crystal substrate, 6 is a gas supply system, 7 is a source gas, 8 is a pipe, 9 is a nozzle, 10 is a flow rate adjustment unit, 11 is an exhaust pump, 15 is a chamber, 15a is a ceiling wall・15b is an exhaust hole, 16 is a rotating shaft, lGa is a flange surface, and 17 is a susceptor. (A) Tree receiving light C Takuue, mutual length fold placement - five generation luxury! Mochi, T same number 1
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Claims (1)

[Claims] An organometallic vapor phase growth apparatus that sprays raw material gas ejected from a plurality of nozzles onto a heated crystal substrate rotating in the same plane to grow an epitaxial layer on the surface of the crystal substrate in a vapor phase. There is a ceiling wall (15a) parallel to and close to the crystal substrate surface.
) The ceiling wall (15a) of the chamber (15) is equipped with a flow rate adjustment unit (10) facing the crystal substrate (5) and aligned in accordance with the size of the crystal substrate (5). A plurality of nozzles (9); and sucking at least upwardly the raw material gas (7) ejected from each of the nozzles (9) at positions substantially equally spaced on both sides parallel to the alignment direction of the plurality of nozzles (9). A metal organic vapor phase growth apparatus characterized by being equipped with an exhaust means.