JPH0426583A - ZnSe crystal growth method and crystal growth device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] E-Industrial Application Field] The present invention relates to crystal growth, and in particular to Z
The present invention relates to a liquid phase crystal growth method and a liquid phase crystal growth apparatus using nSe temperature difference method.

[Prior art] Fig. 4 shows a ■-■ group compound semiconductor Z according to a conventional technique.
A heat sink 6 made of a material with good thermal conductivity such as carbon is housed and fixed at the bottom of a crystal growth ampoule 1 made of quartz showing an nSe liquid phase crystal growth apparatus. On top of the heat sink 6, group Ⅰ element Se or Se-Te is accommodated as the solvent 2. Further, granular polycrystalline ZnSe is accommodated as a source crystal 3 which is a growth material.

After the solvent 2 and source crystal 3 are placed in the growth ampoule 1, the inside of the ampoule is evacuated and sealed. An ampoule having such a configuration is placed in a temperature gradient as shown on the right side of the figure. Then, the source crystal 3 in the upper high temperature part is dissolved in the solvent 2 until it reaches saturation solubility.
Diffuse toward the low temperature area. The melted source crystal 3 is transported through the temperature gradient and reaches near the top surface 7 of the heat sink 6 . Since the temperature near the upper surface 7 of the heat sink 6 is lower than that above, the solution becomes a supersaturated solution, and bulk crystals grow on the upper surface 7 of the heat sink 6 .

The upper surface 7 of the carbon heat sink 6 on which crystals are grown is formed into a flat and mirror surface.

As mentioned above, a crystal growth method in which a temperature difference is created inside the solvent, for example above and below, the source crystal is placed in the high temperature part of the solvent, and the crystal is grown at a constant temperature in the low temperature part of the solvent is called the temperature difference method. .

Problem I that the E-invention aims to solve! ] According to this growth apparatus, source crystal 3 and melt! Due to the difference in specific gravity with 2 and the convection of this solution, it is unclear whether the source crystal 3 is 1 or not. Therefore, the temperature of the source crystal 3 is not constant in the M-density region, and the saturation solubility changes. Further, due to the carbon heat sink 6, the temperature gradient in the solvent 2 becomes steep near the crystal precipitation surface (upper surface 7). Therefore, stable crystal growth with good reproducibility is not performed, and furthermore, the source crystal 3 may fall to the upper surface 7 of the heat sink 6, and no crystal growth may occur.

An object of the present invention is to provide a ZnSe crystal growth method using a temperature difference method, in which the temperature near the source crystal is kept constant and steady crystal growth can be performed with good stability and reproducibility. That's true.

Another object of the present invention is to provide a crystal growth apparatus that can perform such crystal growth.

Means for Solving 3 Problems] According to the present invention, a temperature difference is formed above and below a solvent, a source crystal is placed in a high temperature part of the solvent, and crystal growth is performed at a constant temperature in a low temperature part of the solvent. In the crystal growth method using the method, ingot-shaped Zn used as a source crystal
A method for growing ZnSe crystals is provided, which is characterized in that a Se polycrystal is fixed above a solvent, and the distance between the sos crystal and the surface on which the crystal is deposited is 3 CI or more.

"Function" By fixing the position of the source crystal, the source crystal is always kept at a constant temperature of 1.4 Since the temperature near the source crystal is constant, the saturated solubility becomes constant. Therefore,
The amount of solute diffused into the crystal precipitation area becomes constant, allowing stable crystal growth.

By setting the position where the source crystal is fixed at a distance of 3 degrees or more from the surface on which the crystal is deposited (for example, the carbon surface on the top surface of the heat sink), the source crystal can be placed in a region where the temperature gradient in the solvent is constant.

Therefore, crystal growth is diffusion controlled by the temperature gradient in the solvent, and stable and steady crystal growth with good reproducibility is possible.

Example] FIG. 1 shows a semiconductor crystal growth apparatus for growing ZnSe crystals according to an example of the present invention.

A heat sink 6 made of a material with good thermal conductivity such as carbon is stored in the bottom of a crystal growth ampoule 1 made of quartz, a part of the heat sink 6 is notched, and the growth ampoule 1 is deformed accordingly. This fixes the heat sink 6.

The upper surface 7 of the heat sink 6 (the surface on which crystals are deposited) is treated to be flat and mirror-finished. The heat sink 6 is made of cylindrical high-purity carbon with a diameter of 8 to 201 m and a length of 5 to 2001 m, for example. The quartz ampoule 1 includes a lower small diameter tube 11 and an upper large diameter tube. 12 are connected.

On the mirror-polished upper surface 7 of the heat sink, Se or 5e-Te, which is a group Ⅰ element, is accommodated as the solvent 2. An ingot-shaped ZnSe polycrystal is placed in a quartz ampoule 1 as a source crystal 3 serving as a growth raw material. This ZnSe
The diameter of the polycrystal is larger than the inner diameter of the small diameter part 11 at the bottom of the monoquartz ampule 1 and smaller than the inner diameter of the large diameter part 12. Therefore, the source crystal 3 is held by the step 4 at the connecting portion between the small diameter portion 11 and the large diameter portion 12. After accommodating the solvent 2 and the source crystal 3 in the growth ampoule 1,
The inside of the ampoule 1 is evacuated to a vacuum level higher than 2×10' Torr and sealed.

When the angle 1 having such a configuration is placed in a furnace in which a temperature gradient of the source crystal temperature Ts and the crystal growth start temperature Tg is formed in advance, the right side shows the temperature gradient where the ampoule 1 is placed.

By placing the ampoule 1 in such a temperature gradient, the source crystal 3 in the high temperature portion is dissolved in the solvent 2, transported through the temperature gradient by diffusion, and deposited on the upper surface 7 of the heat sink 6.

Figure 3 shows the holding position of the source crystal 3 and the crystal growth starting point (
This graph shows the relationship between the distance d from the carbon surface 7) and the growth rate V, with Se:Te=3 as the solvent 2.
Using S e - T e of 0+70, growth temperature Tg = 9
50°C, temperature difference ΔT between the source crystal and the growth start point =
This is a graph when shoes are worn at 10°C/C.

Due to the carbon heat sink 6, the temperature gradient in the molten AI2 becomes abrupt near the crystal precipitation area (upper surface 7). Further, the temperature gradient becomes constant as the distance from the crystal precipitation area increases.

Therefore, as shown in FIG. 4, when the value of distance d is small, the growth rate V becomes faster. Also, as the value of distance Md increases,
The growth rate V becomes a constant value to some extent. If the distance Md is small and the growth rate is fast, the precipitated crystals will become polycrystalline. If the distance is 653 cm or more, polycrystalization will not occur, and the crystals will grow at a constant growth rate, resulting in bulk crystals. Obtained.

FIG. 2 shows a semiconductor crystal growth apparatus for growing ZnSe crystals according to another embodiment of the invention! shows.

In this embodiment, the structure of the crystal growth ampoule 1 made of quartz is similar to that in FIG. The shape of this quartz angle 1 is a straight tube. The structure of the heat sink 6 and its fixing method are the same as in the embodiment shown in FIG. Since the solvent 2 and the source crystal 3 are also straight tubes or have an 8-quartz angle 1 shape, which is the same as the embodiment shown in FIG. A manufactured ring 5 is welded to the inner wall of the ampoule 1. The diameter of the ZnSe polycrystal, which is the source crystal 3, is larger than the inner diameter of the quartz ring 5, which is the source crystal stopper, and smaller than the inner diameter of the angle 1. In this way, the source crystal 3 is held. After housing the source crystal 3, a weight 13 is placed on top of it. The zero weight 13, which can also be made of a link-shaped quartz material, may be omitted.

In the same machine as the embodiment shown in FIG. 1, within the growth angle 1, the solvent 2
and after accommodating source crystal 3, inside angle l is Xπ
It is evacuated and sealed.

By placing the ampoule 1 having such a configuration in a temperature gradient as shown on the right side of FIG. 1, the source crystal 3 in the high temperature part is dissolved in the solvent 2 and transported through the temperature gradient. Then, it is deposited on the upper surface 7 of the heat sink 6.

In this embodiment as well, the source crystal 3 is held at a position such that the distance Md to the upper surface 7 of the heat sink 6 on which the crystal is deposited is 3 ci or more.

Therefore, polycrystallization does not occur, and the crystal grows at an almost constant growth rate - a bulk single crystal is obtained.

``Effects of the L Invention'' As explained above, according to the present invention, the position of the source crystal is fixed, and the position is separated by 3 CIs from the surface on which the crystal is deposited.
Since the separation is above, the rate of diffusion of the solute is determined by the constant temperature gradient region in the solvent, and stable and steady crystal growth with good reproducibility is possible.

Furthermore, since crystal growth progresses in an almost constant state from the start to the end of growth, it is possible to grow a bulk single crystal with excellent homogeneity.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view and temperature distribution diagram illustrating a crystal growth apparatus for growing ZnSe crystals according to an embodiment of the present invention, and FIG. 2 is a diagram illustrating a crystal growth apparatus for growing ZnSe crystals according to another embodiment of the present invention. FIG. 3 is a cross-sectional view illustrating a crystal growth apparatus used for this purpose. FIG. 3 is a graph showing the relationship between the distance d between the source crystal position and the crystal growth apparatus section and the growth rate V. FIG. FIG. 2 is a cross-sectional view and a temperature distribution diagram illustrating a liquid phase growth apparatus for growing crystals. Ampoule for crystal growth Se or 5e-Te solvent source crystal step quartz ring heat sink crystal precipitation surface small diameter section large diameter section Fig. 1

Claims (2)

[Claims] (1) In a crystal growth method using a temperature difference method in which a temperature difference is formed above and below the solvent, the source crystal is placed in the high temperature part of the solvent, and the crystal is grown at a constant temperature in the low temperature part of the solvent, as the source crystal. ZnSe is characterized in that the ingot-shaped ZnSe polycrystal used is fixed on the upper part of the solvent, and the distance between the source crystal and the surface on which the crystal is deposited is 3 cm or more.
A method for growing nSe crystals. (2) In a crystal growth apparatus that forms a temperature difference above and below the solvent, places the source crystal in the high temperature part of the solvent, and performs crystal growth at a constant temperature in the low temperature part of the solvent using the temperature difference method. ZnS is placed at a height of at least 3 cm from the top surface of the heat sink.
A ZnSe crystal growth apparatus having a source crystal holding mechanism that holds an e-source crystal.