JPH01141892A - Method for growing crystal - Google Patents

Abstract

PURPOSE:To homogenize a growth melt and to obtain a crystal having uniform composition by oscillating a growth device, and growing a crystal while always oscillating the melt. CONSTITUTION:In the LPE using a tipping method, a growth substrate 2 is set on an inclined surface in a horizontally placed growth vessel 1. A growth melt 3 consisting of Hg, Cd, and Te for example, is charged in the vessel 1, heated by an electric furnace, and melted. The whole growth device is then inclined to place the substrate 2 in a horizontal position L, and the melt 3 is moved to cover the substrate 2 with the melt 3'. Under such conditions, annealing is started, the vessel 1 is oscillated B and T in + or -7.5 deg. amplitude with the horizontal position L as the reference, hence the melt 3' is agitated, the melt 3' is homogenized, and a crystal is grown on the substrate 2.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for growing semiconductor crystals using the LPE method.

[Conventional technology]

Conventionally, the method for growing semiconductor crystals using the LPE method has been described in the Journal of Electrochemical Society; Solid State Science and Technology (J, Electrochem, Soc,: 5
solid-5tate 5science and Te
chnology) magazine, March 1981, No. 128
Volume, No. 3, pages 655-661 and the same magazine, 1983.
As described in January, Vol. 130, No. 1, pp. 228-230, the growth melt that has been melted prior to crystal growth can be grown by tilting the growth device during crystal growth. A method is used in which the crystal reaches the substrate, covers it, and grows crystals on the substrate by slow cooling.

[Problem that the invention seeks to solve]

At this time, the growing melt covers the substrate in a stationary state, so if the melt consists of several components with significantly different specific gravities or if these are not mixed sufficiently, the grown crystals will be as shown in Figure 2 ( As shown in a) and (b), compositional non-uniformity occurs within the plane of the crystal. In particular, as in the example of the above-mentioned literature, the melt is composed of materials such as mercury, cadmium, and tellurium, each having significantly different specific gravities, and the component ratio is, for example, mercury: 18.7%, cadmium: 1.3%, tellurium: 8.
If they are significantly different from 0%, the composition of the grown crystal is likely to be non-uniform.

An object of the present invention is to provide a crystal growth method that eliminates the drawbacks of the conventional methods as described above and has excellent compositional uniformity within the crystal plane.

[Means for solving problems]

The present invention is an LPE growth method using an inclined tipping method, which is characterized in that crystal growth is performed while constantly shaking the growth melt by shaking the growth apparatus during growth.

〔Example〕

Next, the present invention will be explained by examples.

FIG. 1 shows an embodiment of the present invention.

1 is a container for growth made of graphite, and 2 is a substrate made of cadmium telluride for growth. The substrate 2 is set on an inclined surface inside the container 1. 3 is a growth melt before proceeding to crystal growth. The growth melt 3 is filled in the horizontal surface of the container 1.

All of these are vacuum sealed in quartz ampoules.
Further, the ampoule is housed in a swingable electric furnace (none of which is shown).

Crystal growth of mercury cadmium telluride was carried out in the following manner using the growth container 1 described above. First, with the electric furnace in a horizontal position and the growth container l in a horizontal position, the growth melt 3
was made into a molten state.

Next, the entire apparatus was tilted so that the growth substrate 2 was horizontal, so that the growth melt 3 completely covered the substrate 2 (the melt was in the state 3'). FIG. 1 shows this stage, and it is assumed that the substrate 2 is in a horizontal state as L. Normally, slow cooling is started in this state to grow crystals on the substrate 2, but in the present invention, in addition to this, the growth container 1 is rocked, thereby giving movement to the melt 3' and creating a stirring effect. This is intended to prevent partial imbalance of the components of a mixture of mercury, cadmium, and tellurium whose component ratios and specific gravities are significantly different from each other as in this embodiment. The amplitude of the oscillation is 151 degrees, that is, ±7.5° extending between the broken line T and the broken line B with respect to the horizontal state. The larger this value is, the better; however, it is meaningless to give an amplitude to such an extent that the melt 3' cannot cover the substrate 2, so in this embodiment, it is set within this range.

The substrate 2 is horizontal and in the L state, so the growing melt 3
′ completely covered this, the rocking was started once every 30 seconds. Next, slow cooling was started, and after the normal growth time had elapsed, the shaking and slow cooling were stopped, and the crystal growth was completed as usual. Collect the crystals grown on the substrate 2,
As a result of examining the uniformity of the composition within the crystal plane, it was found that as shown in FIG. 3, the number of equal component ratio lines was considerably smaller than that in the conventional method in which no oscillation was performed. This is because the melt is made uniform by the rocking, and non-uniformity due to differences in specific gravity of the components does not occur during growth.

〔Effect of the invention〕

As detailed above, according to the present invention, the uniformity of the melt is promoted while the crystal is growing, or non-uniformity within the melt is prevented during the growth, thereby obtaining a crystal with a uniform composition. It has the effect that it can.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the principle of the present invention, and FIG. 2 is a diagram showing the principle of the present invention. (b) is a diagram showing the composition in the crystal obtained by the conventional method, and FIG. 3 is a diagram showing the composition in the crystal obtained by the present invention.

Claims (1)

[Claims] (1) In the LPE growth method using the inclined tipping method, a crystal growth method is characterized in that crystal growth is performed while constantly shaking the growth melt by applying vibration to the growth apparatus during growth.