JPS6330395A - Method and jig for growing thin film crystal - Google Patents

Abstract

PURPOSE:To obtain a crystal superior in homogeneity by oscillating an ampoule tube in which a base plate and raw materials for growing thin film crystal are separately enclosed in the upper and the lower parts and mixing the raw materials. CONSTITUTION:A base plate supporter which supports the base plate 7 for growing and the raw materials 8 for growing are enclosed in vacuum in the ampoule tube 6. This ampoule tube 6 is set upright to separate the base plate 7 from the raw materials 8 so that the base plate 7 is in the upper position and the raw materials 8 in the lower position, and the raw materials 8 is melted. Then, with the base plate 7 separated from the raw materials 8, the ampoule tube 6 is oscillated from the vertical position to a slanting position to mix the melted liquid of the raw materials 8. And then, the ampoule tube 6 is slanted in the direction opposite to the above-mentioned to bring the base plate 7 into contact with the melted liquid of raw materials. Thus, a thin film crystal is grown on the base plate 7.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for growing thin film crystals by a liquid phase method and a growth jig used therefor, particularly a method for growing thin film crystals by a tilting method and a growth jig used therefor. Regarding jigs.

[Conventional technology] Methods for growing thin film crystals on a substrate using a liquid phase method include the slide port method and the tipping method (tilting method).

There are dipping methods, etc. If the element 11 is composed of elements with low vapor pressure, the open-tube slide boat method is effective, but if it contains elements with high vapor pressure, the closed-tube method is effective. Certain tilting or dipping methods are advantageous. Generally, when trying to grow a thin film crystal, the raw material composition is 2.
It is made up of more than one type of element, and it is necessary to thoroughly mix it in a molten state before growing it. If the mixing is insufficient, crystals with different compositions will grow depending on the location on the substrate or from substrate to substrate. The slide boat method is a method in which mixing is not possible in principle, but the latter three methods are possible.

[Problems to be Solved by the Invention] However, unless the structure of the device is carefully considered, sufficient mixing cannot be expected. For example, as an example of the gradient method, there is an article in "Journal of Electrochemical Society: Solid State Science and Technology" (J.

Electrochem, Soc, : 5OLIf
)-3TATE 5CIENCE AND DING ECHN Kano 0GY) 1981, Volume 128, No. 3, No. 656
Page, and the same <1983, Volume 130, No. 1.

The structures shown respectively on page 229 can be mentioned. In the bender, it is attempted to mix the molten raw material by shaking it in a shallow dish-shaped raw material container, but considering the shape, it can be assumed that sufficient mixing is impossible. In the latter case, no positive intention to mix is recognized. Since these papers did not repeatedly conduct experiments with the same raw material composition and the same temperature conditions, it was not possible to obtain data regarding whether the raw material mixing was sufficient or insufficient.

Therefore, the inventor conducted an experiment using a device similar to the former. The experiment was repeated five times under the same conditions. As a result, although the intended composition of the thin film crystal was hal-xCdxTe with x=O1200, the obtained X values were dispersed from 0.194 to 0.207 at the center position of the substrate.

This result shows that it is difficult to obtain a thin film crystal with a desired composition using a conventional device having a structure that does not allow sufficient mixing.

An object of the present invention is to provide a growth method that can eliminate the drawbacks of conventional methods and improve compositional uniformity when growing thin film crystals by the tilting method, and a growth jig for use therein.

[Means for Solving the Problems] The present invention includes a step of vacuum-sealing a substrate support to which a growth substrate is fixed and a growth raw material into an ampoule tube, and a step of vacuum-sealing a substrate support to which a growth substrate is fixed and a growth material, and a step of vacuum-sealing the ampoule tube in an upright position for growth. A step of separating the growth substrate and the growth raw material vertically and melting the growth substrate, and a step of swinging the ampoule tube back and forth between a vertical position and an inclined position while keeping the growth substrate and growth raw material separated. , a step of mixing the molten raw materials for growth; and a step of, after mixing the raw materials for growth, tilting the ampoule tube in the opposite direction to the above to bring the molten raw materials into contact with the substrate, and growing a thin film crystal on the substrate. A method for growing a thin film crystal, comprising: a hollow ampoule tube containing a growth material; and a substrate support to which a growth substrate is attached and installed in the ampoule tube, the substrate support having: The legs hold the growth substrate at a position above the liquid level of the growth raw material sealed in the ampoule tube, and the transparent part exposes the surface of the growth substrate attached to the substrate support to be brought into contact with the raw material liquid inside the ampoule tube. This is a thin film crystal growth jig characterized by having holes.

[Example] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

As shown in FIGS. 1(a) and 1(b), the growth jig according to the present invention includes a hollow ampoule tube 6 and a substrate support 1 to which a growth substrate 7 is attached and installed inside the ampoule tube 6. Become.

The substrate support 1 has a U-shaped cross section as shown in FIG.
The bottom wall 3 is provided with a through hole (8 x 8 #2) 5 which is slightly smaller than the substrate 7 made of cadmium telluride (10 x 10 x l #3).

The substrate 7 is placed concentrically in the through hole 5 from the inside so that the growth surface faces outward, and the attachment is fixed using a carbon holding plate and screws. As shown in FIG. 1(b), the hollow ampoule tube 6 made of quartz is made by attaching and fixing the substrate 7 to the substrate support 1, and attaching the growth material 81 and the quartz spacer 9 etc. so that the foot part 4 is at the bottom. It is vacuum sealed. The legs 4 are provided with a grip that prevents the 1000 yen 8 from coming into contact with the substrate 7 when the substrate support 1 is in a vertical state as shown in FIG. 1(b).

Next, the method for growing a thin film crystal of the present invention is carried out by the following procedure. That is, first, the growth substrate 7 is fixed to the substrate support 1, and the composition is H.
Mix mercury, cadmium, and tellurium together in 40 Cl to give g 0.20 cdo, 01 TeO, 79 to obtain raw material 8, add spacer 9 to these, and prepare a material with an inner diameter of 25φ as shown in Figure 1 (b). A thermocouple for monitoring (diameter 3 mm >
It is housed in a vertically elongated electric furnace that has an inner diameter that can accommodate both. This electric furnace is installed in an electric furnace that can be tilted from the vertical position (upright) to the left and right by a little less than 90 degrees. Next, as shown in FIG. 2(a), with the ampoule tube 6 in a vertical position and the raw material substrate 7 positioned above the liquid surface of the raw material 8, the electric furnace is heated to melt the raw material 8 at 530'C. After leaving it for - hours, turn the electric furnace 9 so that the open side of the substrate support 1 to which the substrate 7 is not fixed is facing downwards, as shown in FIG. 2(b).
Tilt slightly less than 0°. This angle is an angle i at which the ampoule tube 6 is inclined so close to horizontal that the molten growth raw material 8 does not come into contact with the lower end of the spacer 9. After being left in this state for 3 minutes, the ampoule tube 6 was returned to the upright position again to obtain the state shown in (a), and after approximately 3 minutes, it was again brought back to the state shown in (b). This repeated process was continued for 1 hour to ensure thorough mixing of the molten raw materials, and finally the state was returned to (a). Next, the growth temperature is lowered to 500°C, and when the temperature has settled down to that temperature, the molten raw material 8 is tilted slightly 90' to the opposite side from the previous step in order to contact the substrate 7, and the temperature is gradually reduced at 0.2°C per minute. A thin film crystal of mercury cadmium telluride was grown on the substrate 7 while cooling. After 2 hours, the electric furnace was returned to the state of (a), the molten raw material 8 was separated from the substrate 7, the power to the furnace was turned off, and the furnace was cooled to room temperature. When the substrate was taken out from the quartz ampoule, a crystal with a thickness of approximately 201M1 had grown.As a result of repeating this growth five times, the Cd value at the center position on the substrate varied from 0.197 to 0. The distribution was up to 203. This value can be said to be considerably better than the method with insufficient mixing.

[Effects of the Invention] As explained above, according to the present invention, when growing compound thin film crystals consisting of various elemental compositions by the liquid phase gradient method, raw materials can be sufficiently mixed, resulting in uniform composition. Crystals with excellent properties can be obtained. It goes without saying that this invention can be applied not only to mercury cadmium telluride in the examples but also to other compounds.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the thin film crystal growth apparatus of the present invention.
a) is a perspective view showing the substrate support; (b) is an overall view;
Figures (a), (b), and (c) are explanatory diagrams of the thin film crystal growth method of the present invention. 1... Board support 2... Side wall 3... Bottom wall 4... Foot portion 5... Through hole
6...Quartz ampoule tube 7...Substrate
8... Raw material for growth 9... Spacer

Claims (2)

[Claims] (1) The process of vacuum sealing the growth substrate and the growth raw material supported by the substrate support into an ampoule tube, and the step of vertically separating the growth substrate and the growth raw material by standing the ampoule tube vertically. and a step of mixing the melted growth raw material by swinging the ampoule tube back and forth between a vertical position and an inclined position while keeping the growth substrate and the growth raw material separated. , after mixing the growth raw materials, tilting the ampoule tube in the opposite direction to the above to bring the molten raw materials into contact with the substrate, and growing the thin film crystal on the substrate. Method. (2) It has a hollow ampoule tube that accommodates the growth raw material, and a substrate support to which a growth substrate is attached and installed in the ampoule tube, and the substrate support is provided with a solution of the growth raw material sealed in the ampoule tube. A thin film characterized by having feet for holding the growth substrate in a position above the surface, and a through hole for exposing the surface of the growth substrate to be brought into contact with the raw material solution attached to the substrate support into the ampoule tube. Jig for crystal growth.