JPS5918194A - Liquid-phase epitaxial growth - Google Patents

Abstract

PURPOSE:To form a high-quality epitaxial crystal growth in a large area, by setting a good heat conductor members in a solution in a liquid reservoir of a sliding member sliding on a base support, keeping the temperature of the solution in a uniform state. CONSTITUTION:The carbon lamellar members 14, a good heat conductor, having about 2-3mm. thickness free from impurity, are inserted into the jig 15, and set in the solution 13 of Hg1-xCdxTe put in the liquid reservoir 12 of the sliding member 11. The base 17 of CdTe is embedded in the support 16, and the material 13 is packed into the liquid reservoir 12 of the sliding member 11. A device for epitaxial growth is inserted into a reaction tube in a hydrogen gas atmosphere, the reaction tube is heated by a furnace so that the material 13 is melted. The temperature of the solution in the liquid reservoir 12 is uniformed by the carbon member 14. In this state, the sliding member 11 is transferred in the B direction, the liquid reservoir 12 is allowed to stand on the base 17, and the crystal layer of the material 13 is uniformly formed on the base 17 while the temperature of the furnace is lowered at a given temperature gradient.

Description

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

(b) Background of the technology Materials for forming photoelectric conversion elements such as infrared sensing elements include:
Compound semiconductor crystals containing mercury (H2), such as mercury, cadmium, tellurium (Ib'l-x cax-1"e)
It is well known that a compound semiconductor crystal with a narrow leggy gap such as the one shown in FIG.

"Formation of devices using such HfH-x CdxTe crystals"
A trap to obtain a large area and a thin layer so that two parts are good is cadmium chloride /L/(Cd 1'e
), and on it the above-mentioned Hy,z CdxT
The crystal layer e is formed by a liquid phase epitaxial growth method using a sliding method.

(c) Prior Art and Problems The conventional method of liquid phase epitaxial growth will be explained with reference to FIG.

As shown in the figure, a CdTe substrate 3 is embedded in a recess 2 of a rectangular parallelepiped-shaped support base 1 made of carbon.

On the other hand, a square shell 111 is attached to a rectangular parallelepiped-shaped slide member 4 made of carbon that slides on the support base 1.
A liquid reservoir 5 consisting of one hole is provided, and a substrate 3 is placed inside the liquid reservoir 5.
A solution of the material 6 of Hyl, Cdx'l''e of the crystal layer to be formed above is filled.

After inserting an epitaxial growth apparatus consisting of a support stand 1 and a slide member 4 as shown in FIG.
Heat to temperature.

After that, the material in the transfer basin 5 melts and Hy, -xCdxT
When the solution 6 of e is formed, move the slide member 4 in the direction of arrow A.
After moving the liquid reservoir 5 in the direction on the substrate 3, the temperature of the heating furnace is lowered at a predetermined temperature gradient to grow an epitaxial layer of JCHy, -xCdx Te on the substrate 3. There is.

However, recently, even in photoelectric conversion elements such as the above-mentioned infrared detection elements, there has been a demand for large-scale integration of elements within a single crystal substrate. It is becoming increasingly desirable to form epitaxial crystal layers.

By the way, in order to form such a large-area epitaxial crystal layer, the volume of the liquid reservoir 5 must be increased, and when the volume of the liquid reservoir 5 is increased in this way, the solution in the peripheral area of the liquid reservoir is increased. The temperature and the temperature of the solution in the center of the liquid reservoir are different, and it is difficult to make the temperature of the solution in the liquid reservoir uniform, resulting in fluctuations in the thickness of the epitaxial crystal layer that is formed and protrusions. This may cause inconveniences such as crystal defects in materials, etc.

The thickness of the solution in the solution reservoir, which is related to the growth of epitaxial crystals, is only a few hundred micrometers, so the thickness of the solution in the solution reservoir must be adjusted so that the temperature of the solution in the reservoir is uniform. Attempts have been made to achieve epitaxial growth by increasing the thickness of the solution, but when the thickness of the solution is reduced in this way, the surface tension of the solution causes the solution to collect locally or to the substrate. When the slide member is slid after epitaxial growth, the solution rolls due to the spherical shape 7, causing the inconvenience that it cannot be sufficiently wiped off from the substrate.

(d) Purpose of the Invention The present invention aims to eliminate the above-mentioned drawbacks and to obtain an epitaxial crystal layer with a large area by providing a solution in which the temperature of the solution in the reservoir is uniform even when a large-capacity reservoir is used. The purpose of this paper is to provide a novel liquid phase epitaxial growth method.

(e) Structure of the Invention In order to achieve the above object, the liquid phase Evitakireya growth method of the present invention includes a growth apparatus comprising a support base in which a substrate is embedded and a slide member that slides on the support base and moves on the support base. Member K, a method for epitaxially growing a crystal layer on a substrate after providing a liquid reservoir containing a solution of a material for a crystal layer to be formed on a substrate and leaving the liquid reservoir stationary on the substrate; This device is characterized in that a good thermal conductor member is placed in the solution to keep the temperature of the solution in the reservoir uniform.

(f) Embodiment of the Invention An embodiment of the invention will be described in detail below with reference to the drawings.

FIG. 2 is a cross-sectional view of an apparatus used in the liquid phase epitaxy growth method of the present invention, and FIG. 3 is a plan view of the main part of the apparatus with the liquid reservoir portion enlarged.

The difference between the liquid phase epitaxial growth method of the present invention and the conventional method is that, as shown in FIGS. 2 and 3, a thermal A plurality of plate-like members 14 made of carbon having a thickness of about 2 to 3 N are provided, which are good conductors and do not contain impurity components such as metal elements. The plate-like member 14 made of carbon is installed by cutting grooves at a predetermined pitch so that it is inscribed in one part of the liquid reservoir hole (, l, -xCd, To) (as shown in Fig. 3). The member 14 is installed so as to be inserted into the jig 15, and a predetermined distance is left so that the bottom of the member 14 does not come into contact with the two sides of the support base 16. When the slide member 11 is slid in the direction of arrow B. , and avoid contact with the CdTe substrate.

Next, CdTe was grown using the liquid phase epitaxial growth apparatus consisting of the slide member 11 and the support base 16 as described above.
u) To describe the case of forming a crystal layer of Ih, -XCdXTe on the substrate 17, the CdTe C1) substrate 17 is buried in the support base 16 mentioned above, and the slide part @■
A material 13 of I(yl-XCdXTe) is charged into the liquid reservoir 12 of .

Thereafter, the epitaxial growth apparatus is inserted into a reaction tube in a hydrogen (Iω gas atmosphere), and the reaction tube is heated in a heating furnace to melt the H, CdxTe material.
Even if the capacity of the solution reservoir 12 becomes large, heat flows uniformly into the solution due to the plate-shaped carbon member 14 having good thermal conductivity, so that the temperature inside the solution becomes uniform.

Thereafter, the slide member 11 is moved in the direction of arrow B to place the liquid reservoir 12 on the substrate 17, and while lowering the temperature of the heating furnace at a predetermined temperature gradient, the liquid reservoir 12 is placed on the substrate 17 by KHf'+-xCdx.
A crystal layer of Te is formed.

In this way, Hrhx Cdz T in the liquid reservoir 12
Since the liquid phase moon of e is kept at a uniform temperature, CdTe
The advantage is that a high-quality epitaxial crystal layer free from crystal defects can be obtained over a large area on the substrate 17.

In the above examples, a carbon member was used to equalize the temperature of the solution in the liquid reservoir, but any material other than carbon may be used as long as it does not contain impurity components such as metals and is a good thermal conductor. It's okay.

(g) Effects of the Invention As described above, the method of the present invention has the advantage that a large-area epitaxial crystal layer can be obtained in a high-quality state without crystal defects.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an apparatus used in a conventional liquid phase epitaxial growth method, and FIGS. 2 and 3 are a sectional view and a plan view of essential parts of an apparatus used in a liquid phase epitaxial growth method of the present invention. 1 and 16 are support stands, 2 is a recess, 3゜17 is a CdTe substrate, 4 and 11 are slide members, 5 and 12 are liquid reservoirs, 6 and 13 are liquid phases of Hf+-x Cd, To,]
Reference numeral 4 indicates a carbon member, and reference numeral 15 indicates an installation jig.

Claims (1)

[Claims] A growth apparatus comprising a support base in which a substrate is buried and a slide member that slides on the support base, and a liquid reservoir containing a solution of a material for a crystal layer to be formed on one substrate is provided in the slide member, and In a method of epitaxially growing a crystal layer on a substrate after placing a liquid reservoir on the substrate,
A liquid phase epitaxial growth method characterized in that a good thermal conductor member is installed in the solution in the liquid reservoir to maintain the temperature of the solution in the reservoir in a uniform state aK.