JPS58115100A - Preparation of single crystal of inorganic compound - Google Patents

Abstract

PURPOSE:To obtain a disc-shaped single crystal wafer having large diameter, by specifying the relations between the direction of the long axis of the boat, the <111> direction and the (110) face in the preparation of a single crystal of a III-V group compound by boat growth process. CONSTITUTION:The symbols 2, 3, 4 and 5 represent the single crystal of a III-V group compound obtained by the boat growth process, the direction of the long axis of the boat or the direction of the growth of the single crystal, the <111> direction, and the upper surface or free surface of the single crystal, respectively. In the preparation of the single crystal 2, the directions 3 and 4 are adjusted to be included essentially in the (110) face, and the direction 4 is titled from the direction 3 toward the bottom of the boat by <=5 deg.. When the angle of tilt exceeds 5 deg., the obtained wafer is distorted. A disc-shaped (100) face III-V group compound wafer having a diameter of >40mm. can be manufactured by the present process from a single crystal obtained by the use of a boat having a diameter of about 50mm..

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a single crystal of an inorganic compound (hereinafter referred to as a "rut-v group compound").

Single crystals of m-'v group compounds, particularly GaAs, are generally produced by boat growth methods such as the temperature gradient method (GF method) and the horizontal Bridgman method (HB method).

However, since the wafer cut from the obtained single crystal has a semicircular shape, when such a wafer is used, it can be used as an FET.

There is a problem in that it is difficult to automate the manufacturing process of elements such as I'C.

In general, in the boat growth method, from the viewpoint of single crystal quality, yield, etc., the <///> direction coincides with the growth direction, that is, the boat growth direction, and the (/10) plane coincides with the vertical plane. selected. The plane of the sea urchin cut out from such a single crystal is shown in FIG. 1, which is cut out from a single crystal obtained by the boat growth method. Since the diameter of the boat is usually about jO1lII+, when cutting a circular ueno from the rice ball-shaped ueno obtained by using this boat, only a circular (100)-sided eba with a diameter of about 36 m can be obtained. In addition, increasing the diameter of the boat had four problems, including the need to increase the size of the electric furnace and a decrease in single crystal yield.

The present inventor has arrived at the present invention as a result of intensive research aimed at developing a method for producing a single crystal sea urchin, a compound of the ■-■ group, which has eight circular shapes with a larger diameter than conventional methods. .

The above object of the present invention is to provide a method for producing a single crystal of a V-group compound by a boat growth method, in which the major axis direction and the <///> direction of the single crystal growth boat are substantially aligned with the (/10) plane. , and the method is characterized by tilting the < /// > direction toward the bottom of the boat so that the < /// direction makes an angle of 7 or less with the major axis direction. This can be achieved by

The present invention will be explained based on the drawings.

FIG. 2 is a partial perspective view of a single crystal of a group I-■ compound obtained by the boat growth method.

In FIG. 2, 2 is the long axis direction of the elliptical boat obtained by the boat growth method, that is, the growth direction of the single crystal. Arrow d indicates the <///> direction. j is the upper surface of the single crystal, the so-called free surface.

In order to produce a group IV compound single crystal by the method of the present invention, long sleeve direction 3 and (/// > direction V are substantially (i
io) included in the plane and tilted so that the angle makes an angle of less than 50 with respect to 3 towards the bottom of the boat; In this case, the range of 2 to 0 is more preferable, and if it exceeds j'', the crystallinity will deteriorate and the yield of single crystal will decrease. It is desirable to have a shape of 0. If it exceeds jo, the shape of ueno will be distorted, so it is not preferable.

The single crystal growth method is the usual boat growth method, for example, G
This is carried out by the F method, HB method, etc.

According to the method of the present invention, even if a single crystal produced using a boat with a diameter of about 50 m is used, it is possible to produce a circular (IO surface 111-V group compound sea urchin) whose diameter exceeds ≠0III+. Therefore, there is no need for a large electric furnace, and furthermore, there is no need to use a large boat, which tends to deteriorate the yield of single crystals, so the industrial value is extremely great.

Next, the present invention will be explained in more detail based on Examples.

EXAMPLE A GaAs single crystal was grown using a GF method single crystal manufacturing apparatus whose vertical cross-sectional front model is shown in FIG. In Figure 3, 6
is a quartz boat for single crystal growth.

7 is a part of the boat 6 on which the seed crystal is placed.

♂ is a sealed quartz tube in which the boat 6 is enclosed, and ♂ is made of As and heated to about tio° C. in an electric furnace IO to prevent GaAs from decomposing near its melting point. /l is boat 6
It is an electric furnace for heating the furnace, which is divided into several parts and controlled in order to obtain the required temperature gradient. 12 is a SiC furnace core tube used to smooth the temperature gradient.

Polycrystalline GaAs is placed in a quartz boat with a semicircular cross section and a length of 3 squares. OQ? I charged it. 8 to this
1 to 0. ．． 2f was added. Place the seed crystal on the seed crystal placement part 7 of the boat 6, so that the (/10) plane coincides with the vertical plane,
and<///>The growth direction is defined such that the A8 direction and the long axis direction of the boat A are included in the (/10) plane, and the (iti>A8 direction is tilted downward by ≠0 from the long axis direction). .

The above boat was sealed together with As in a quartz sealed tube.

This sealed tube is charged into an electric furnace, and the electric furnace IO is heated.

℃. Further, regarding the electric furnace //, the seed crystal part of the boat 6 was controlled at /230°C and the other end at 1210°C, so that the temperature distribution therebetween was substantially linear.

After each part of the electric furnace reached a predetermined temperature, the temperature of the electric furnace/l was lowered at a temperature lowering rate of o, j'c/hour.

An (ioo) plane wafer was cut from the obtained single crystal, and a circular wafer with a diameter of 1 m was obtained from the wafer. The etch pit density (EPD) of the obtained wafer was 7. j X' / 03/cry! And ivy.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a wafer cut from a boat-grown single crystal. FIG. 2 is a partial perspective view of a single crystal obtained by the boat growth method. FIG. 3 is a vertical cross-sectional front model view of the GF method single crystal manufacturing apparatus. l...Wafer 3...Boat's long axis direction ≠...
Person Patent Attorney Hase - (7 others)

Claims (1)

[Claims] In a method for producing a single crystal of an inorganic compound consisting of a Group I element and a Group V element of the periodic table by a boat growth method,
The long sleeve direction and the </I//> direction of the single crystal growth boat are substantially included in the (llO) plane, and the above <///
A method characterized in that the <///> direction is tilted toward the bottom of the boat such that the > direction and the major axis direction form an angle of 50 or less.