JPH025515A - Organic metal vapor growth device - Google Patents

Abstract

PURPOSE:To form even epitaxial layers effectively on a crystal substrate by a method wherein multiple nozzles provided with cavity parts passing through the outer periphery of the nozzles in parallel with the same are arranged on the position close to a crystal substrate as if covering the whole surface of the crystal surface while an exhaust system sucking a material gas in the direction reverse to the jetting direction of the same is directly connected to the cavity parts. CONSTITUTION:A vacuum pump 11 is driven to evacuate a chamber 15 down to around 0.1 atmospheric pressure while a material gas 7 controlled by flow rate controllers 10 is blown at the flow rate of, e.g., 2-3m/sec upon the surface of a crystal substrate 5' heated at around 650 deg.C by a susceptor 17 to form a specified epitaxial layer on the surface. At this time, the residual material gas 7 after finishing the specified epitaxial deposition on the surface of the crystal substrate 5' is sucked at the cavity regions C formed around respective nozzles 19 to be firstly turned into the gas flow (5) and secondly the other gas flow (6) when passing through the other gap regions D between a nozzle unit 18 and the chamber 15 and then externally exhausted by the vacuum pump 11.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a metal-mechanical vapor phase growth apparatus for manufacturing semiconductor devices by a vapor phase growth method, and is aimed at efficiently forming a uniform epitaxial layer on a crystal substrate. A metal-organic vapor phase growth apparatus that grows an epitaxial layer on the surface of a crystal substrate in a vapor phase by spraying source gas with a controlled flow rate ejected from a plurality of nozzles onto the surface of the crystal substrate, A plurality of nozzles each having a cavity extending parallel to the nozzle around the outside of the nozzle are arranged so as to cover the entire surface of the crystal substrate, and a plurality of nozzles are placed in the cavity in a direction opposite to the direction in which the source gas is ejected. It is constructed by directly connecting an exhaust means for suction.

[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 growth apparatus that efficiently forms a uniform epitaxial layer on a crystal substrate to improve productivity.

When forming an epitaxial layer on a heated crystal substrate in a chamber by spraying a gas containing raw material components (hereinafter referred to as raw material gas) on the substrate, the amount of raw material components diffused into the crystal layer on the substrate is It largely depends 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.

[Conventional technology]

FIG. 2 is a diagram illustrating an example of a conventional vapor phase growth apparatus, in which (A) shows the overall configuration, and B) and (C) are enlarged views of the main parts to explain the flow of gas. It is.

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

Further, the crystal group Fi5 to be processed, which forms an epitaxial layer on the surface (upper surface in the figure), is centered so as to coincide with the rotation center of the susceptor 4.

On the other hand, the raw material gas 7 sent out from the raw material gas supply system 6 passes through the piping 8 and is ejected onto the surface of the crystal substrate 5 from a plurality of nozzles 9 installed near the top of the chamber 1. Since a good epitaxial layer can be obtained by changing the flow rate of the ejected raw material gas 7 depending on the position of the nozzle, a flow rate adjustment section 10 is provided in front of the nozzle 9 so that the flow rate for each nozzle can be adjusted.

Note that reference numeral 11 in the figure is an exhaust pump for discharging the raw material gas 7 after the diffusion process has been completed on the surface of the crystal substrate 5.

Here, the pressure inside the chamber 1 is reduced to about 0.1 atm, and while the crystal substrate 5 is heated to about 650°C by the susceptor 4 and the rotating shaft 2 is rotated at about 60 rpm, for example, trimethylindium TMIn, ) ethyl Gallium T
Hydrogen gas H using 3113 as raw material to EGa + arsine
2 as a carrier is blown onto the surface of the crystal substrate 5 at a flow rate of 2 to 3 m/s6 (as shown in the figure),
For example, an epitaxial layer of indium, gallium, and arsenic (InGaAs) 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 outlet of the nozzle.

When raw material gas is jetted from each nozzle in this state, for example, raw material gas 7b jetted from nozzles 9b and 9c,
7c progresses in the two directions indicated by ■ and ■ in the figure while performing epitaxial growth on the surface of the crystal substrate 5.

- The raw material gases 7a and 7d ejected from the nozzles 9a and 9d at both ends advance 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
Two mountains are formed.

On the other hand, the film thickness distribution in the Y direction forms a distribution curve C1 having 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 crystal substrate 5
Good results can be obtained when the diameter of the crystal substrate is, for example, 2 inches or less, but as the diameter increases, the deviation of the film thickness composition and carrier concentration from the average values in the peripheral area of the crystal substrate increases, making it difficult to achieve uniformity. − This makes it difficult to form an epitaxial layer.

[Problem to be solved by the invention]

With conventional vapor phase growth equipment, there is a problem in that it is not possible to form a uniform and stable epitaxial layer on crystal substrates with large diameters (e.g., 3 inches or more), and there is also the problem that productivity due to simultaneous operation on multiple substrates cannot be achieved. There was a problem in that it was difficult to improve the performance.

[Means to solve the problem]

The above-mentioned problem is an organometallic vapor phase growth apparatus in which an epitaxial layer is grown in a vapor phase on a heated crystal substrate surface by spraying source gas with a controlled flow rate ejected from a plurality of nozzles onto the surface of the crystal substrate. , a plurality of nozzles having voids extending parallel to the nozzles around the outside of the nozzles are disposed in close proximity to the crystal substrate so as to cover the entire surface of the crystal substrate, and a raw material gas is supplied to the voids. This problem can be solved by an organometallic vapor phase growth apparatus that is directly connected to an exhaust means that sucks in a direction opposite to the ejection direction.

[For production]

In order to always form a stable and uniform epitaxial layer on a large-diameter crystal substrate, new raw material gas is constantly supplied to every position on the crystal substrate, and the remaining raw material gas after epitaxial growth is passed through other positions. It is necessary that the gas be evacuated as quickly as possible.

In the vapor phase growth apparatus of the present invention, nozzle units having a size sufficient to cover the entire surface of a crystal substrate are arranged with gaps so that the raw material gas ejected from the nozzles can be immediately discharged from around the nozzles. It consists of multiple nozzles.

Therefore, after the controlled source gas ejected from the nozzle performs epitaxial growth on the crystal substrate, it is discharged as it is from the gap formed around the nozzle without flowing over the substrate, so that it remains stable on the crystal substrate. A uniform epitaxial layer can be formed.

〔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 (A) is a side cross-sectional view, and (B) is a diagram illustrating the main part of the nozzle unit.

In addition, in the figure, for ease of understanding, the case where there is one crystal substrate will be explained.

In FIG. 1(A), a base 16 having a flange surface 16a on the upper part is fixed to the chamber 15.
A susceptor 17 made of carbon and heated by a coil 3 provided on the outer periphery of the chamber 15 is disposed on the flange surface 16a.

Further, the crystal substrate 5'' to be processed, similar to that shown in FIG.
It is placed in a predetermined position.

On the other hand, the raw material gas 7 sent from the raw material gas supply system 6 passes through a pipe 8S and then passes through a plurality of nozzles 19, which are components of a nozzle unit 18 installed near the top of the chamber 15, to the crystal substrate 5'. It erupts on the surface of
At this time, a flow rate adjustment section 10 is provided immediately before each nozzle 19 so that the flow rate of the ejected raw material gas 7 can be changed depending on the position of the nozzle.

11 in the figure is an exhaust pump for discharging the raw material gas 7 after the epitaxial growth has been completed on the surface of the crystal substrate 5'', as in FIG. 2.

In addition, in the figure (B) showing a cutaway plan view at the a''-a' section in figure (A), there are a plurality of nozzle units 18 (the figure shows 19
The cylindrical nozzles 19 are arranged in a hexagonal shape in close contact with each other, and the outer periphery of the nozzles 19 is fixed with a fixing plate 18a made of, for example, quartz.
The lower end 18b on the crystal substrate 5' side of a is connected to each nozzle 19.
The susceptor 17 is installed so as to protrude somewhat more and to be in contact with the upper surface of the susceptor 17 over its entire length.

In this case, the source gas 7 ejected from each nozzle 19 is forced to leave the triangular prism-shaped void area C formed around each nozzle 19 after colliding with the 5° surface of the crystal substrate.

Here, the exhaust pump 11 is operated to bring the inside of the chamber 15 to zero.
．． The pressure is reduced to about 1 atm, and the crystal substrate 5'' is placed on a susceptor 17.
In the state heated to around 50°C, the raw material gas 7 controlled by the flow rate controller 10 as in FIG.
A desired epitaxial layer is formed on the surface of the crystal substrate 5'' by spraying it onto the surface of the crystal substrate 5'' as shown in the figure (2) at a flow rate of c.

At this time, the remaining raw material gas 7 after the predetermined epitaxial growth has been completed on the surface of the crystal substrate 5' is sucked into the void area C formed around each nozzle 19, and becomes . The exhaust gas passes through the gap area between the exhaust pumps 15 and 15 and is discharged to the outside from the exhaust pump 11.

Therefore, in a vapor phase growth apparatus having such a configuration, a controlled new raw material gas can be constantly supplied to the entire surface of the crystal substrate, and the remaining raw material gas after the growth is suctioned and discharged as it is without flowing over the crystal substrate 5'. Therefore, a uniform and stable epitaxial layer can be formed on the surface of the crystal substrate 5' regardless of the size of the crystal substrate.

Although one crystal substrate 5° is placed in the chamber 15 in the figure, it is also possible to place a plurality of crystal substrates in the same chamber in exactly the same manner.

〔Effect of the invention〕

According to the present invention, it is possible to provide an organometallic vapor phase epitaxy apparatus that can simultaneously form uniform and characteristically stable epitaxial layers on a plurality of crystal substrates.

[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, and FIG. 2 is a diagram illustrating an example of a conventional vapor phase growth apparatus. In the figure, 3 is a coil, 5' is a crystal substrate, 6 is a raw material gas supply system, 7 is a raw material gas, 8 is a pipe, 10 is a flow rate adjustment section, 11 is an exhaust pump, 15 is a chamber, 17 is a susceptor, and 18a is a 19 represents a fixed plate, and 19 represents a nozzle. 16 is the base, 18 is the nozzle unit, 18b is the lower end, (A)

Claims (1)

[Scope of Claims] A metal-organic vapor phase growth apparatus for growing an epitaxial layer on a heated crystal substrate surface by spraying source gas with a controlled flow rate ejected from a plurality of nozzles onto the surface of the crystal substrate. A plurality of nozzles each having a cavity extending parallel to the nozzle around the outside of the nozzle are disposed in a position close to the crystal substrate so as to cover the entire surface of the crystal substrate, and further, in the cavity,
A metal organic vapor phase growth apparatus characterized by being directly connected to an exhaust means for sucking in a direction opposite to the direction in which source gas is ejected.