JPS62241343A - Vapor phase epitaxial growth device - Google Patents

Abstract

PURPOSE:To enable a boundary layer, which is uniform in thickness, to be formed over a wide range on a substrate, by extending a susceptor supporting bed with respective given lengths in the directions of upstream and downstream sides of a reaction gas against a substrate-set position so that is formed with the same angle as that of susceptor inclination. CONSTITUTION:A susceptor 12 made of plate graphite, on which a semiconductor substrate 11 of compound such as CdTe is mounted, is buried in a susceptor supporting bed 13 so that the surface of this susceptor 12 has the same angle thetaas that of the surface of the susceptor supporting bed 13. And, the susceptor supporting bed 13 is extended as for as l and l' from upstream and downstream end parts 12A and 12B of the susceptor 12 respectively against a gaseous flow shown using an arrow B. Thus, without a rapid change in the gaseous flow occurring on the gaseous upstream side end part 11A and downstream one 11B of the substrate 11, a boundary layer 14, which is uniform in thickness (t), can be formed over a wide range on the substrate 11.

Description

[Detailed Description of the Invention] [Summary] A susceptor support stand that supports a susceptor holding a substrate of a vapor phase epitaxial growth apparatus, wherein the susceptor support stand is located at both ends of the susceptor on an upstream side and a downstream side of a reaction gas. On the other hand, the epitaxial layer is formed to extend a predetermined dimension at the same angle as the inclination angle of the susceptor, and a boundary layer of the reactant gas is formed on the substrate with a uniform thickness. A vapor phase epitaxial growth device that ensures uniform thickness and composition.

[Industrial application field]

The present invention relates to a vapor phase epitaxial growth apparatus.

Compound semiconductor crystals such as mercury-cadmium-tellurium (Hg, -xCdXTe) have a narrow energy gap and are therefore used as materials for photoelectric conversion devices such as infrared sensing elements.

In order to obtain such Hg + -x Cd x T e with a uniform composition and over a large area for convenience in device formation, organic metal compounds containing cadmium or tellurium, and metal mercury and hydrogen gas are used. A reaction gas consisting of cadmium tellurium (CdT) is introduced into the reaction tube.
e) A vapor phase epitaxial growth method is used to grow Hg+-xCdxTe on a substrate.

[Conventional technology]

As shown in FIG. 3, such a vapor phase epitaxial growth apparatus is designed so that the flow of the reaction gas introduced into the reaction tube 1 rises from the upstream side to the downstream side, as shown by arrow A. A susceptor support stand 2 having a slope of about 100 mm is installed, and a susceptor 4 made of graphite on which a compound semiconductor substrate 3 such as cadmium tellurium (CdTe) is installed is installed on top of the susceptor support stand 2.

Here, dimethyl cadmium, diethyl tellurium, and hydrogen gas carrying mercury are introduced into the reaction tube 1.
By passing a high-frequency current through a coil 5 provided on the outer wall of the susceptor 4, the susceptor 4 is heated and the substrate 3 thereon is heated, and Hg is generated on the surface of the substrate by the thermal decomposition reaction of the introduced reaction gas.
An epitaxial layer of +-x Cd X Te was formed.

[Problem that the invention seeks to solve]

However, in such a conventional device, as shown in FIG.
A, 2B and both ends 4 of the susceptor 4 installed thereon
A and 4B have a structure in which they are aligned, and in such a structure, as shown in FIG. arise. In addition, the reaction gas flowing above the substrate 3 is transferred to the end 4B of the susceptor and the end 2B of the susceptor support on the downstream side of the gas.
Since the boundary layer peels off and vortices are generated, there is a problem that the boundary layer 6 is not uniformly formed on the substrate 3.

To explain this boundary M6, for example, when a fluid hits an object, the movement of the fluid is such that outside the thin layer scratched on the surface of the object, the fluid flows in a turbulent state, and the surface of the object A very thin layer near the object is a viscous fluid flowing through it, and this thin viscous fluid layer near the object is called a boundary layer.

In this boundary layer part, the flow of the reactant gas is stable in a laminar flow state, so the composition of the epitaxial layer that is formed when this boundary layer part is expanded over a wide range on the substrate, The thickness is said to be uniform.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a vapor phase epitaxial growth apparatus in which a boundary layer of a reactive gas is formed with a uniform thickness over a wide range on a substrate.

[Means for solving problems]

The vapor phase epitaxial growth apparatus of the present invention includes a substrate, a susceptor on which the substrate is placed, a susceptor support base for supporting the susceptor, and a reaction tube into which the susceptor support base on which the substrate and the susceptor are installed, In the apparatus for epitaxial growth by introducing a reaction gas into the reaction tube and growing the components of the reaction gas on the substrate, the susceptor support table has the same inclination angle with respect to the susceptor on which the substrate is installed. , and is formed to extend by a predetermined dimension from both ends of the susceptor on the upstream side and the downstream side with respect to the flow of the reaction gas.

(Function) In the vapor phase epitaxial growth apparatus of the present invention, the susceptor support of the susceptor that holds the substrate extends by a predetermined dimension in the upstream and downstream directions of the reaction gas with respect to the position where the substrate is installed. It is formed at the same angle as the inclination angle of the susceptor, so that there is no fluctuation in the gas flow at both ends of the substrate along the gas flow, and a boundary layer with a uniform thickness is formed over a wide range on the substrate. to be done.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is an explanatory diagram of an implementation of the vapor phase epitaxial growth apparatus of the present invention.

As shown in the figure, in the device of the present invention, a susceptor 12 made of plate-shaped graphite on which a compound semiconductor substrate 11 such as CdTe is placed is buried in a susceptor support base 13, and the surface of this susceptor 12 and the susceptor support The susceptor 12 is buried in the susceptor support base 13 so as to form the same angle θ as the surface of the base 13.

Further, the susceptor support base 15 used in the present invention is arranged so that the susceptor 12 has a gas upstream direction 0II with respect to the gas flow shown by the arrow B.
J end 12A and gas downstream end 12B of the susceptor 12
The distance l, and ! °Dimensions are extended.

By doing this, the gas upstream end 11 of the substrate 11
8. At the gas upstream end 11B of the substrate 11, a boundary layer 14 with a uniform thickness is formed over a wide range on the substrate 11 without seeing any sudden changes in the gas flow.

In this embodiment, a vapor phase epitaxial growth apparatus using the MOCVD method was described, but the present invention is also applicable to MOCVD.
It is applicable not only to the D method but also to other vapor phase epitaxial growth apparatuses.

Further, in this embodiment, the inclination angle of the susceptor support is set to θ, but the angle θ may be 0 degrees.

〔Effect of the invention〕

As described above, according to the apparatus of the present invention, a boundary layer is formed over a wide range with a uniform thickness on the substrate during epitaxial growth, resulting in high-quality epitaxial crystals with stable composition and thickness. There is an effect that can be obtained.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing an embodiment of the vapor phase epitaxial growth apparatus of the present invention, Fig. 2 is an explanatory diagram of a conventional vapor phase epitaxial growth apparatus, and Fig. 3 is an explanatory diagram showing an inconvenient state in the conventional apparatus. It is. In the figure, 11 is the substrate, IIA and IIB are the ends of the substrate, 12 is the susceptor, 12^ and 12B are the ends of the susceptor, 13 is the susceptor support, and 14 is the boundary layer. +Child September Shiebi 7 Mother〉Yru→4. Figure 1 of the device's original date and time; Fig. 1;

Claims (1)

[Claims] A substrate (11) and a susceptor (on which the substrate (11) is installed)
12), and a susceptor support stand (13) that supports the susceptor.
), a reaction tube into which is inserted a susceptor support (13) on which the substrate (11) and the susceptor (12) are installed,
In the apparatus for introducing a reaction gas into the reaction tube and thermally decomposing components of the reaction gas onto the substrate (11) for epitaxial growth, the susceptor support (13) is provided with the substrate (11). With respect to the susceptor (12), both ends (12A, 12B) of the susceptor (12) have the same inclination angle, and are on the upstream side and downstream side with respect to the flow of the reaction gas.
) A vapor phase epitaxial growth apparatus characterized by being extended by a predetermined dimension.