JPS63185889A - Vapor epitaxial growth device - Google Patents

Abstract

PURPOSE:To make it possible to form an epitaxial layer having clear boundary of epitaxial layer made on a wafer by change of gas and excellent facial uniformity, by setting both a specific gas flow changing means and a partition plate in a vapor epitaxial growth reaction tube. CONSTITUTION:A substrate 8 is set in a vapor epitaxial growth reaction tube 2 and raw material gases 3 and 9 are supplied to grow an epitaxial layer on the substrate 8. In the reaction tube 2 are set the following gas flow changing means 6 and partition plate 5. Namely, the partition plate 5 is horizontally set from a position in the upper stream of the substrate 8 arranged in the reaction tube 2 to a position in the downstream of the substrate 8 and divides the reaction tube 2. The gas flow changing means 6 is arranged at the tip part of the upper stream side of the partition plate 5 and can change the ratio of a raw material gas flowing at the side of the substrate 8 at a section in the direction perpendicular to the longer direction of the reaction tube 2 at the position of the gas flow changing means 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a vapor phase epitaxial growth apparatus, specifically a vapor phase epitaxial growth method for forming an epitaxial layer with clear vapor phase epitaxial growth layer boundaries and improved surface uniformity. Regarding equipment.

[Prior Art] When growing two or more epitaxial layers using a vapor phase epitaxial growth apparatus, various gas flow switching methods have been proposed in order to clearly define the boundaries between each layer over a wide area of the wafer surface. There is. Examples of this include changing the position of the switching valve attached to the piping that connects to the reaction tube, creating multiple upstream material supply chambers and switching them using a rotary valve, or installing a cover on the board that can be slid open and closed. There are several ways to install it.

Devices using conventional gas switching methods, such as those described above, simply change the type and flow of gas and do not stop growth, so the boundaries formed by gas switching are unclear. Ta. Furthermore, in the method of temporarily stopping growth by covering the wafer, the in-plane uniformity of the epitaxial layer was poor because the gas flow rate did not change.

[Object of the Invention] An object of the present invention is to solve the above-mentioned problems and to provide a method in which the boundaries of the epitaxial layer formed on the wafer by gas switching are clear and the surface uniformity is good. An object of the present invention is to provide a vapor phase epitaxial growth apparatus capable of forming a certain epitaxial layer.

[Configuration of the Invention] The apparatus of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows a specific example of the apparatus of the present invention, which includes a heater 1, a cylindrical quartz reaction tube 2, a growth gas population 3, a raw material source port 4, a partition plate 5, and a gas flow variable means for changing the gas flow. 6, a rod 7, a substrate 8 and a gas port 9. The gas flow variable means 6 is a rotating plate, and can be rotated by rotating the rod 7.

The gas flow variable means 6 can change the proportion of the area of the cross section perpendicular to the longitudinal direction of the reaction tube on the substrate side in the gas flow variable means portion, thereby changing the proportion of the gas flow flowing toward the substrate side. . The angle between the plane perpendicular to the longitudinal direction of the reaction tube and the gas flow variable means is preferably about 30 to 60 degrees. Furthermore, as an alternative to the method of changing the proportion of the cross-sectional area on the substrate side, the gas flow variable means can be changed with the connecting portion of the gas flow variable means and the partition plate as the axis (i.e., the direction perpendicular to the plane of the paper is the central axis). A method of changing the angle up and down may also be used.

To form an epitaxial layer on a wafer using the apparatus shown in FIG.
Supply raw material gas and stabilize the inside of the reaction tube. Next, when the rod is rotated so that the rotary plate 6, which is facing downward, is turned upward, the substrate side (i.e., the lower side of the partition plate 5) of the gas flowing downstream of the reaction tube along the rotary plate 6 is The amount of gas passing increases, and the gas passing over the substrate 8 maintains a laminar flow state while increasing its flow velocity, making it possible to grow an epitaxial layer with improved in-plane uniformity. .

In order to continuously grow another epitaxial layer on the layer formed in this way, after forming the desired first layer from step 1 above, turn the rotary plate 6 downward again and start epitaxial growth. After stopping the reaction, change the gas type or flow rate to stabilize the condition inside the reaction tube.
Repeat the above steps to perform another epitaxial growth.

By repeating this operation, an epitaxial layer with a clear epitaxial layer interface over a wide range can be formed.

Example 1 An epitaxial layer was formed using the apparatus shown in FIG. In this case, the inner diameter of the reaction tube 2 was 100 mm, and GaAs was used as the substrate.

By bubbling AsCQz at room temperature with H gas at 1.012/min, a mixed gas of ASC+23 and 02 was supplied from 3. The total flow rate of gas supplied through pipes 3 and 9 was 1.5 Q/min.

Ga was put into the raw material source port 4. source port 4
The temperature of the substrate 8 is 820-870°C, and the temperature of the substrate 8 is 710-770°C.
An epitaxial layer of GaAs was grown on the substrate at 40°C. Before doping by supplying 1000 ppm-cc of H and S from 9, the rotating plate 6 was turned downward to temporarily stop the growth.

After 20 seconds, it was doped with it, and after another 20 seconds, epitaxial growth was performed with the rotary plate 6 facing upward.

FIG. 2 shows the dopant distribution in the depth direction of the epitaxial layer thus obtained. Also, the distribution of the epitaxial layer obtained using the conventional growth apparatus is shown by the dashed line. Furthermore, when the in-plane uniformity was measured at a point 6 mm from the top and bottom edges toward the center, the variation in the epitaxial layer grown using the conventional device was 5 to 10%, whereas the variation in the epitaxial layer grown using the device of the present invention was 5 to 10%. The variation in the epitaxial layer that was grown using the same method was 3% or less (using a 40 mmφ substrate), and the quality of the epitaxial layer was improved.

[Effects of the Invention] By using the apparatus of the present invention, the epitaxial layer boundary becomes clear due to switching of gas flow rate and gas type during epitaxial growth, and in-plane uniformity is improved.
“Since it is possible to grow epitaxial wafers for PET, Schottky diodes, and Gunn diodes, where n-type dopants are grown in multiple layers, or InGaA
s/I nP, AQGaΔs/GaAs heterostructure epitaxial wafer, GaAs/InAs, fnG
High performance products can be obtained using the apparatus of the present invention in areas such as aAs/Af2LnAs multilayer heterostructure epitaxial wafer growth.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a specific example of the device of the present invention, and FIG.
The figure is a graph showing the dopant distribution in the depth direction of epitaxial layers grown by the apparatus of the present invention and the conventional apparatus. DESCRIPTION OF SYMBOLS 1... Heater, 2... Reaction tube, 3... Growth gas supply port, 4... Raw material source port, 5... Partition plate, 6... Gas flow variable means, 7...
- Rod, 8... Board, 9... Gas supply port.

Claims (1)

[Scope of Claims] 1. A vapor phase epitaxial growth apparatus for growing an epitaxial layer on the substrate by disposing a substrate in a vapor phase epitaxial growth reaction tube and supplying source gas, the reaction tube comprising: a gas flow variable means; It has a partition plate, and the partition plate is arranged horizontally from upstream of the substrate disposed in the reaction tube to downstream of the substrate to partition the reaction tube, and the gas flow variable means is arranged on the upstream side of the partition plate. A vapor phase epitaxial growth apparatus, which is arranged at the tip and is capable of changing the proportion of the raw material gas flowing toward the substrate in a cross section perpendicular to the longitudinal direction of the reaction tube at the position of the gas flow variable means. . 2. The growth apparatus according to claim 1, wherein the gas flow variable means is a rotating plate, and the rotating plate can be rotated by rotating a rod attached to an end of the rotating plate. 3. The growth apparatus according to claim 1 or 2, wherein the gas flow variable means is inclined at about 30 to 60 degrees from a plane perpendicular to the longitudinal direction of the reaction tube.