JPH0475652B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to an improvement in a liquid phase epitaxial growth apparatus.

(b) Conventional Background Compound semiconductor crystals such as mercury, cadmium, and tellurium (Hg _1-X Ca _X Te), which have narrow energy gaps, are generally used as materials for forming infrared sensing elements.

In order to form such crystals in a thin layer of single crystal over a large area for convenient device formation,
A relatively inexpensive and easily available single-crystal cadmium telluride (CaTe) substrate is used, and Hg _1-X
A method of growing Ca _X Te crystals by liquid phase epitaxial growth has been used.

By the way, the crystals of _{Hg 1-X} Ca The device was previously proposed.

(c) Prior Art and Problems FIG. 1 is a sectional view of such a conventional liquid phase epitaxial growth apparatus. As shown in the figure, a pair of support members 1 made of cylindrical quartz or the like are provided with a recess 4 for installing a CaTe substrate 2 and a substrate installation stand 3 made of quartz for supporting the substrate 2. These support members 1 are housed in a heat-resistant quartz sealed tube 5 so as to be inscribed therein.

The epitaxial layer forming material 6 of Hg _{1-X Ca} is heated to melt the epitaxial layer forming material 6, and then the sealed tube 5 is rotated to bring the molten material into contact with the substrate, and then the temperature of the heating furnace is lowered to form an epitaxial layer on the substrate. I have to.

However, in such a conventional device, there is a drawback that the substrate 2 is cracked or chipped when the substrate 2 is held on the support member 1, and it takes too much time to attach the substrate 2.

Therefore, as shown in FIG. 2, the present inventors provided an appropriate protrusion inside the heat-resistant sealed tube 11, for example, on the upper surface of a rectangular parallelepiped container 12 whose one side serves as an opening/closing lid.
A CaTe substrate 13 is placed parallel to the upper surface, and Hg _1-X Ca _X Te is placed at the bottom of the container 12.
The opening/closing lid (not shown) is closed and the support rod 15 made of quartz is filled with the epitaxial layer forming material 14.
The container 12 is fixed inside the sealed tube 11 using a screw. After that, the sealed tube 11 is inserted into the heating furnace to melt the epitaxial layer forming material 14, and then the sealed tube 11 is rotated to bring the epitaxial layer forming material 14 into contact with the substrate 13, and then the temperature of the heating furnace is lowered. An epitaxial layer is formed on the substrate.

By the way, when such epitaxial layer forming material 14 is melted, impurities in the carbon jig used to form the material or the container 12 may be removed.
A thin film-like sludge is formed due to oxides of the material due to a trace amount of oxidizing gas remaining in the material, or crystal nuclei generated when the material is melted, and this sludge forms the substrate 13 in a solution. When brought into contact with the substrate surface, the epitaxially grown layer may not grow due to the sludge, or crystal defects may occur in the grown layer.

(d) Object of the Invention The present invention eliminates the above-mentioned drawbacks and provides a novel liquid phase epitaxial growth apparatus which prevents the above-mentioned sludge from adhering to the epitaxial layer surface when forming an epitaxial layer on a substrate. It is intended for the purpose of providing.

(e) Structure of the Invention In order to achieve the above object, the liquid phase epitaxial growth apparatus of the present invention accommodates a substrate and a crystal layer forming material to be epitaxially grown on the substrate in a heat-resistant sealed tube so as to face each other. , in a configuration in which crystal growth is performed by bringing the substrate into contact with a solution of the crystal layer forming material by rotating the sealed tube in a state in which the crystal layer forming material is melted, a portion of the substrate at the bottom of the substrate when the sealed tube is rotated; First, a partition plate is provided so that one edge thereof is in contact with the solution of the crystal layer forming material through a minute gap from the inner wall surface of the sealed tube, and the partition plate is rotated integrally with the heat-resistant sealed tube. By letting
It is characterized in that the sludge on the solution is removed by the partition plate.

(f) Embodiments of the invention Examples of the invention will be described in detail below with reference to the drawings. FIG. 3 is a cross-sectional view of the liquid phase epitaxial growth apparatus of the present invention, and FIG. 4 is a longitudinal cross-sectional view of the apparatus.

As shown in the figure, the liquid phase epitaxial growth apparatus of the present invention comprises a hollow cylindrical container 21 made of quartz with a bottom and a disc-shaped opening/closing lid 22 that can be attached to and removed from the opening of the container. Here, the container is assumed to be cylindrical for convenience of explanation, but it may be a rectangular parallelepiped used in conventional devices, or the container may be a sealed tube itself as shown in FIG. This opening/closing lid 22 has a protrusion 23 that fits into the container 21. This opening/closing lid 22
After opening, a CaTe substrate 24 is placed in the upper part of the container 21 so as to substantially contact the inner wall of the container 21 using a quartz protrusion 25 formed inside the container 21 .

On the other hand, a partition plate 26 made of quartz is installed near the lower part of the substrate 24 by a protrusion 27 made of quartz formed on the inner wall of the container 21 .

Next, an epitaxial layer forming material 28 of Hg _1-X Ca _X Te to be formed on the substrate 24 is placed in the lower part of the container 21.
After filling the container and evacuating the inside of the container, open and close the lid 22.
Close. Thereafter, the container 21 is placed in a bottomed quartz tube 29.
While the container 21 is held in the quartz tube 29 by a support rod 30 inserted therein and made of quartz, the inside of the quartz tube is evacuated to form a sealed tube.

Thereafter, such a sealed tube 29 is inserted into a heating furnace, and the temperature of the heating furnace is increased to melt the Hg _1-X Ca _X Te material 28 . Even if there is some gap between the container and the lid, the surface tension of Hg will prevent the Hg _1-X Ca _X Te solution from spilling outside. This state is the fifth
As shown in the figure. Hg _1-X Ca _X Te material 2 as shown
The above-mentioned sludge 31 is formed on the partition plate 8, and the distances l ₁ and l ₂ between the partition plate 26 and the inner wall of the container 21 are set such that l ₂ > l _1.
1 so that they are in contact with each other. Also this l ₁ and l ₂
Which of these should be increased depends on the direction of rotation of the container.

Next, the sealed tube 29 is rotated in the direction of arrow A in FIG. 5 to bring it into the state shown in FIG. 6. As shown in the figure, the rotating tip of the partition plate 26 comes into contact with the solution before the substrate 24, so that the sludge 31 is pushed to one side by one edge of the partition plate 26.

Next, the sealed tube is further rotated in the direction of arrow B to bring it into the state shown in FIG. Sludge 31 as shown
are further gathered in one place by a partition plate 26.

Next, the sealed tube is further rotated in the direction of arrow C to bring it into the state shown in FIG. Sludge 3 as shown
Hg _1-X 1 is scooped up and collected on the top of the partition plate 26, and the substrate 24 is immersed.
Almost no sludge 31 exists in the _CaXTe solution 28. In this state, the temperature of the heating furnace is lowered to form an epitaxial layer of Hg _1-x Ca _X Te on the substrate 24 .

Thereafter, the sealed tube is further rotated in the direction of arrow D to obtain a state as shown in FIG. Sludge 3 as shown
1 is collected at a predetermined location by the other edge of the partition plate 26 and no longer adheres to the substrate 24.

Next, the sealed tube is rotated in the direction of arrow E to bring it into the state shown in FIG. As shown in the figure, an epitaxial layer having a flat surface to which sludge 31 and the like are not attached is formed on the substrate 24.

(g) Effects of the Invention As described above, according to the liquid phase epitaxial growth apparatus of the present invention, an epitaxial layer containing an easily evaporable component such as Hg can be obtained in a flat state, and such epitaxial crystals can be grown in a flat state. Forming an infrared sensing element using this method has the advantage of improving the yield of element formation.

[Brief explanation of the drawing]

1 and 2 are a cross-sectional view and a plan view of a conventional liquid phase epitaxial growth apparatus, and FIGS. 3 and 4 are a cross-sectional view and a vertical cross-sectional view of a liquid-phase epitaxial growth apparatus of the present invention. , FIG. 5 to FIG. 10 are diagrams showing the operating state of the liquid phase epitaxial growth apparatus of the present invention. In the figure, 1 is a support member, 2, 13, 24 are
CaTe substrate, 3 is the substrate installation stand, 4 is the recess, 5, 1
1, 29 are sealed tubes, 6, 14, 28 are Hg _1-X Ca _X Te
12, 21 are containers, 15, 30 are holders, 22 are opening/closing lids, 23, 25, 27 are projections, 2
6 is a partition plate, 31 is a sludge, A, B, C,
D and E indicate the direction of rotation of the container, and l ₁ and l ₂ indicate the distance between the partition plate and the container.

Claims (1)

[Claims] 1. A substrate 24 and a crystal layer forming material 28 to be epitaxially grown on the substrate are placed facing each other in a heat-resistant sealed tube 29, and the crystal layer forming material 28 is melted. In a configuration in which crystal growth is performed by bringing the substrate 24 into contact with the solution of the crystal layer forming material 28 by rotating the sealed tube 29, the substrate 2 at the time of rotation of the sealed tube is placed below the substrate 24.
A partition plate 26 is provided with one edge thereof being in contact with the solution of the crystal layer forming material 28 with a minute gap from the inner wall surface of the sealed tube 29, and the partition plate 26 is connected to the heat-resistant seal. A liquid phase epitaxial growth apparatus characterized in that the sludge 31 on the solution is removed by the partition plate 26 by rotating it integrally with the tube 29.