JPS63198322A - Semiconductor crystal growing apparatus - Google Patents

Abstract

PURPOSE:To obtain an epitaxially grown layer having good crystallinity and uniformity by providing a plurality of pin inserting holes for replacing pins for holding a wafer at a wafer susceptor to alter the position of the wafer to an optimum position responsive to growing conditions merely by replacing the pins. CONSTITUTION:A plurality of pin inserting holes 5 to be inserted with pins 4 are so formed at a wafer susceptor 1 as to freely elevationally move a wafer 3, pins 4 are so inserted to the holes 5 as to disposed the wafer 3 at the optimum position matched to growing conditions, and the wafer 3 is placed thereon. Thus, even when the growing conditions are altered, the position of the wafer 3 can be changed merely by replacing the pins 4, and an epitaxial layer having excellent crystallinity and uniformity can be always obtained even if the susceptor 1 is not replaced.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is directed to MO
The present invention relates to a CVD apparatus, and particularly to a semiconductor crystal growth apparatus for obtaining a uniform epitaxial layer with good controllability.

[Conventional technology]

Conventionally, MOCVD has been used as a method for growing thin films of III-V compound semiconductors and the like.

FIG. 2 is a schematic diagram of a reaction tube and a susceptor of a conventional MOCVD apparatus.

In FIG. 2, 1 is a wafer susceptor, 2 is a susceptor holder that supports the wafer susceptor 1, 3 is a wafer fixed to the wafer susceptor 1, 6 is a quartz reaction tube, and 7 is for induction heating of the wafer susceptor 1. RF coil 8 is a carrier gas containing source gas.

Next, the operation of the MOCVD apparatus will be explained using an example in which epitaxial growth of an AuGaAs crystal is performed.

First, a wafer 3 on which a GaAs substrate crystal is placed is inserted into a quartz reaction tube 6 at a predetermined position on a wafer susceptor 1, and then a high frequency current is passed through an RF coil 7 to remove a wafer susceptor made of carbon, which is a conductor. 1 is heated by induction. At this time, the raw material gas (
A mixture of AsH3, TMG, TMA) and H2 gas is supplied from the gas inlet at the top of the quartz reaction tube 6.

After the wafer susceptor 1 is heated to around 700 to 800°C by induction heating, raw material gas whose flow rate is precisely controlled by a mass flow controller is introduced, thereby causing a thermal decomposition reaction on the surface of the wafer 3 heated to a high temperature. is deposited as AJZGaAs. Note that in order to improve uniformity, the wafer susceptor 1 is slowly rotated in accordance with the rotation of the susceptor holder 2.

[Problem that the invention seeks to solve]

The crystallinity, uniformity, etc. of the epitaxial growth layer are determined by the epitaxial growth temperature, gas flow rate, etc., but they are also influenced by the shape of the wafer susceptor 1, the position of the wafer 3, etc. Among them, the optimum position of the wafer 3 is determined. is expected to vary depending on growth conditions.

However, the conventional wafer susceptor 1 has a problem in that the position of the wafer 3 is fixed and cannot be changed freely.

This invention was made to solve the above-mentioned problems.The wafer susceptor can be changed freely without replacing the wafer susceptor, and the wafer can be grown at the optimal position according to the growth conditions. An object of the present invention is to provide a semiconductor crystal growth apparatus which is configured as follows.

[Means for solving problems]

In the semiconductor crystal growth apparatus according to the present invention, the wafer susceptor is provided with a plurality of pin insertion holes for replacing wafer holding pins so that the wafer position can be freely changed to an optimal position that matches the growth conditions. It is something that

(Function) In this invention, when epitaxial growth is performed by changing the growth temperature, changes occur in the thermal decomposition reaction process near the wafer susceptor due to the influence of thermal convection, and a uniform epitaxial layer cannot be obtained at the previous position. In some cases, by replacing the wafer holding pins and moving the wafer to the optimal position, a uniform epitaxial layer can be obtained without replacing the wafer susceptor.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

In Figure 2, 1 to 3 are the same as in Figure 2, and 4
5 is a wafer holding pin for holding the wafer 3 in a predetermined position, and 5 is a plurality of pin insertion holes provided in the wafer susceptor 1 for replacing the pin 4.

In order to allow the wafer 3 to move freely in the vertical direction, a plurality of pin insertion holes 5 into which pins 4 are inserted are provided, and the pins 4 can be easily replaced at desired positions.

Next, a case in which epitaxial growth of an AJZ GaAs crystal is performed according to the present invention as in the conventional example will be described as an example.

First, the pin 4 is inserted into the pin insertion hole 5 of the wafer susceptor 1 so that the wafer 3 is placed at an optimal position matching the growth conditions, and the wafer 3 is placed thereon. Then, the wafer susceptor 1 is inserted into a 5-Engine reaction tube 6 as shown in FIG. Introduce.

On the wafer 3, source gas (A s H3, TMGTM
A) is thermally decomposed and AIL is produced through the following chemical reaction.
A GaAs layer is grown.

2ASH3+Ga (CH3)3 +Au(CH3)3
-AuGaAs+6CH4 In the conventional wafer susceptor 1, the position of the wafer 3 was fixed and could not be changed freely, but according to the present invention, even when changing the growth conditions, the position of the wafer 3 can be changed simply by replacing the pin 4. The position can be changed, and an epitaxial layer with excellent crystallinity and uniformity can always be obtained without replacing the wafer susceptor 1.

In the above embodiments, the epitaxial growth of an AuGaAs-based compound semiconductor was explained as an example, but the present invention is not limited to this, but can also be applied to crystal growth apparatuses in general using a thermal decomposition reaction method, and also to other semiconductor materials. It has a similar effect.

〔Effect of the invention〕

As explained above, the present invention provides a wafer susceptor with multiple pin insertion holes for replacing wafer holding pins so that the wafer position can be freely changed to the optimal position depending on the growth conditions. Since the wafer is provided, the position of the wafer can be changed to the optimum position according to the growth conditions simply by replacing the wafer holding pin, and an epitaxially grown layer with good crystallinity and uniformity can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a side view of a wafer susceptor used in an MOCVD apparatus showing an embodiment of the present invention, and FIG.
FIG. 2 is a cross-sectional side view showing the reaction system of the VD device. In the figure, 1 is a wafer susceptor, 2 is a susceptor holder, 3 is a wafer, 4 is a pin for holding the wafer, and 5 is a pin insertion hole. Note that the same reference numerals in each figure indicate the same or corresponding parts. Figure 1 Procedural amendment (voluntary) To 1932 March 24 ET 1. Indication of the case Japanese Patent Application No. 82-32019 2. Title of the invention Semiconductor crystal growth apparatus 3. Person making the amendment 5. Specification subject to amendment Detailed Description of the Invention Column 6, Contents of Amendment (1) "Figure 2" on page 5, line 4 of the specification is amended to read "Figure 1." (2) Similarly, "mass flow float roller" in lines 1 and 2 of page 6 is corrected to "mass flow controller."that's all

Claims (1)

[Claims] In an MOCVD device that grows crystals on a wafer using a thermal decomposition reaction of a raw material gas, the wafer is held by wafer holding pins provided on a wafer susceptor, and the wafer is positioned at an optimum position according to the growth conditions. 1. A semiconductor crystal growth apparatus characterized in that said wafer susceptor is provided with a plurality of pin insertion holes into which said wafer holding pins are transferred in order to hold the wafer in a certain position.