JPH0624894A - Device for liquid phase epitaxy of multielement semiconductor crystal - Google Patents

Abstract

PURPOSE:To obtain a multi-element semiconductor crystal with the composition stabilized by using this device for liq. phase epitaxy by the closed-tube dipping method. CONSTITUTION:This device has a closed quartz tube 1 which is horizontally pivoted and freely turned to an angle of 180 deg., an almost columnar substrate fixer 2 to be inserted into the tube 1 having a segmental circular-sectioned recess 21 obtained by notching the periphery of the fixer 2 almost at its center and a rectangular recess 32 formed almost at the center of a flat surface 31 and into which a crystal substrate 5 is inserted, and is provided with a substrate holder 3 with the surface on the opposite side of the flat surface 31 having a barrel protrusion 35. The recess 21 is charged with a fixed amt. of a multi- element semiconductor soln. 7, the substrate 5 is horizontally held by the substrate holder 3, the protrusion 35 is directed toward an opening, the holder is placed in the recess 21, and the holder 3 is turned over by the fixer 2 by turning the closed quartz tube 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid phase epitaxial growth apparatus for multi-element semiconductor crystals, and more particularly to a liquid phase epitaxial growth apparatus for a closed tube type tipping method.

A multi-element semiconductor crystal containing an easily-evaporable element as a main component is often grown on the surface of a crystal substrate by a closed tube tipping method.

[0003]

2. Description of the Related Art FIG. 3 is a side sectional view of a conventional liquid phase epitaxial growth apparatus, and FIGS. 4A and 4B are views for explaining the operation of a conventional example.

In the figure, 7 is a multi-component semiconductor solution which is liquefied by heating a multi-component semiconductor crystal material (eg Hg, Cd, Te). Reference numeral 5 is a crystal substrate made of a multi-element semiconductor crystal such as a cadmium tellurium (CdTe) crystal and has a plate thickness of 0.5 mm to 1 mm.

1 has a horizontal shaft 11 provided at both end surfaces,
It is a hollow cylindrical quartz closed tube that is horizontally pivoted so that it can rotate 0 degrees. Reference numeral 2 denotes a cylindrical substrate fixing body made of quartz that is inserted into and fixed to the closed quartz tube 1.

In the central portion of the substrate fixing body 2, a desired long cross section circular recess 21 having a cross section larger than a semicircle and parallel to the axis is provided. By providing the recess 21 having a circular cross section in this manner, the substrate fixing body 2 is composed of a pair of columnar bodies on both sides and a fan-shaped body portion 22 connecting the both columnar bodies.

Reference numeral 30 denotes a thin rectangular plate-shaped substrate holder made of quartz, in which a shallow rectangular concave portion 32 substantially equal to the planar shape of the crystal substrate 5 is provided on one flat surface 31. By horizontally pushing the crystal substrate 5 into the rectangular recess 32, the crystal substrate 5 is placed in the substrate holder 30 with the surface slightly protruding from the flat surface 31.
It is mounted on the flat surface 31 side of.

On the other hand, the end faces 23 of the recess 21 having a circular cross section are opposed to each other.
A guide groove is provided on both of the above so as to face the position of the fan-shaped portion 22 from the axis. The left and right side edges of the substrate holder 30 are inserted into and fixed to the guide grooves facing each other so that the crystal substrate 5 is on the side of the fan-shaped portion 22, and the substrate holder 30 is horizontally mounted in the recess 21 having a circular cross section. There is.

Then, a predetermined amount of multi-source semiconductor crystal material is put into the recess 21 having a circular cross section, the substrate fixing body 2 having the substrate holder 30 is inserted into the quartz closed tube 1 and fixed, and then the inside pressure of the quartz closed tube is reduced to a desired pressure. Then, the opening of the quartz closed tube 1 is sealed.

The predetermined amount of the multi-source semiconductor crystal material means that when the quartz closed tube 1 is held so that the fan-shaped body portion 22 of the substrate fixing body 2 is located above when the multi-source semiconductor solution 7 is heated. As shown in FIG. 4 (A), the closed quartz tube 1 is rotated 180 degrees so that the substrate holder 30 is above the liquid surface of the multi-source semiconductor solution 7 and the fan-shaped portion 22 of the substrate fixing body 2 is located below. Then, as shown in FIG. 4B, the crystal substrate 5 is immersed in the multi-component semiconductor solution 7.

Using the liquid phase epitaxial growth apparatus as described above, liquid phase epitaxial growth of a multi-element semiconductor crystal on the surface of a crystal substrate is performed as follows. The quartz closed tube 1 in which the multi-source semiconductor crystal material (eg Hg, Cd, Te) and the crystal substrate (CdTe crystal plate) 5 are sealed is put in an electric furnace and heated to 500 ° C., as shown in FIG. 4 (A). Thus, the multi-source semiconductor crystal material is liquefied to form a multi-source semiconductor solution (Hg, Cd, Te solution) 7.

Next, after cooling the closed quartz tube 1 to a saturation temperature (480 ° C.) or lower, the closed quartz tube 1 is rotated 180 degrees, and FIG.
As shown in FIG. 2, the substrate holder 30 is turned upside down and the crystal substrate 5 is laid horizontally downward, so that the substrate is immersed in the multi-element semiconductor solution 7 and brought into contact with the multi-element semiconductor crystal (mixed crystal of HgTe and CdTe).
Are grown on the surface of the crystal substrate 5.

At the time when the film has grown to a desired film thickness (for example, 50 μm), the quartz closed tube 1 is inverted to separate the multi-element semiconductor solution 7 and the crystal substrate 5 and stop the growth. In addition, on the surface of the crystal substrate, mercury cadmium tellurium (Hg
A semiconductor component provided with a multi-element semiconductor crystal composed of CdTe) crystal is widely used as an infrared detector.

The molecular formula of mercury cadmium tellurium crystal is Hg
_{In 1-x} Cd _X Te, the bandgap of the mercury-cadmium tellurium crystal is determined by the X value (Cd amount), and in the case of an infrared detector, the response wavelength is predetermined by the X value.

[0015]

By the way, when a mercury cadmium tellurium crystal material (HgCdTe) is melted, since the specific gravity of HgTe is larger than that of CdTe, a concentration gradient of HgTe occurs in the depth direction of the solution.

On the other hand, in the conventional liquid phase epitaxial growth apparatus, when the quartz closed tube is rotated 180 degrees to bring the crystal substrate and the multi-source semiconductor solution into contact with each other, the surface tension of the multi-source semiconductor solution causes a diagram shown in FIG. 4 (B). As described above, a part of the multi-source semiconductor solution P remains on the flat back surface 33 of the substrate holder.

Then, the multi-component semiconductor solution P attached and left on the substrate holder is not constant but different every time. That is, in FIG.
Due to the fact that the liquid surface height H of the multi-source semiconductor solution shown in (B) is different each time, the concentration of the multi-source semiconductor solution in the portion in contact with the surface of the crystal substrate 5 is changed, and the multi-phase semiconductor crystal that undergoes liquid phase epitaxial growth However, the composition becomes unstable, and a multi-component semiconductor crystal component having predetermined characteristics cannot be obtained.

The present invention has been made in view of the above points, and an object thereof is to provide a liquid phase epitaxial growth apparatus capable of obtaining a multi-component semiconductor crystal having a stable composition.

[0019]

In order to achieve the above object, the present invention, as shown in FIG. 1, encloses a crystal substrate and a multi-source semiconductor crystal material in a quartz closed tube and heats it to form a closed tube type. A device for contacting and separating a crystal substrate and a multi-component semiconductor solution by the tipping method to perform liquid-phase epitaxial growth of a multi-component semiconductor crystal on the surface of the crystal substrate. 1, a substantially cylindrical substrate fixing body 2 inserted into the quartz closed tube 1, and a substrate fixing body 2
A circular concave section 21 having a cross-section lacking in the substantially central portion and a rectangular concave section 32 for pressing and setting the crystal substrate 5 in the substantially central portion of the flat surface 31.
And a substrate holder 3 in which the surface opposite to the flat surface 31 is formed as a semi-cylindrical convex surface 35.

The concave section 21 having a circular cross section has the function of a container for containing a predetermined amount of the multi-element semiconductor solution 7. In the substrate holder 3, the crystal substrate 5 is horizontal and the kamaboko-shaped convex surface 35 faces the opening side. In this state, the substrate is mounted in the recess 21 having a circular cross section, and the substrate fixing body 2 is adapted to turn upside down the substrate holder 3 by rotating the closed quartz tube 1.

[0021]

In the substrate holder according to the present invention, the surface of the substrate opposite to the mounting surface of the crystal substrate is a semi-cylindrical convex surface. Therefore, when the quartz closed tube is inverted 180 degrees and the crystal substrate is brought into contact with the multi-element semiconductor solution, , The convex side of the kamaboko is on the upper side.

This prevents the multi-component semiconductor solution from adhering to and remaining on the kamaboko-shaped convex surface. That is, since the height of the liquid surface of the multi-component semiconductor solution becomes constant every time during the liquid phase epitaxial growth, the concentration of the multi-component semiconductor solution in the portion in contact with the surface of the crystal substrate becomes constant.

Therefore, the composition of the multi-element semiconductor crystal grown by liquid phase epitaxial growth is constant and stable.

[0024]

The present invention will be described in detail with reference to the drawings. The same reference numerals denote the same objects throughout the drawings.

FIG. 1 is a diagram of an embodiment of the present invention, (A) is a perspective view showing a separated form, (B) is a sectional view of a substrate holder, and (A) and (B) of FIG. FIG. 6 is a diagram for explaining the operation of the present invention. The liquid phase epitaxial growth apparatus shown in FIGS. 1 and 2 differs from the conventional apparatus in the substrate holder on which the crystal substrate is mounted.

Therefore, the description of the quartz closed tube, the substrate fixing body, the crystal substrate and the like is the same as that of the conventional structure, and therefore will be omitted. Three
Is a shallow rectangular recess 32 that is substantially equal to the planar shape of the crystal substrate 5.
Is a substrate holder made of quartz, which is provided substantially at the center of the flat surface 31, and the surface opposite to the flat surface 31 is formed as a semi-cylindrical convex surface 35.

By horizontally pushing the crystal substrate 5 into the rectangular recess 32 of the substrate holder 3, the crystal substrate 5 is projected to the flat surface 31 side of the substrate holder 3 with the surface slightly protruding from the flat surface 31. It will be installed.

Then, a circular cross-section concave portion 21 of the substrate fixing body 2 is formed.
Guide grooves 24 are provided so as to oppose each other at a position closer to the fan-shaped portion 22 than the axial center of both end faces of the crystal substrate 5 with the fan-shaped portion.
The right and left side edges of the substrate holder 3 are inserted into and fixed to guide grooves 24 facing each other so that they are on the 22 side, and the substrate holder 3 is set in the recess 21 having a circular cross section so that the crystal substrate 5 becomes horizontal. It is installed in.

The substrate fixing body 2 is divided into two parts on a plane including the lower surface of the guide groove 24. A predetermined amount of multi-source semiconductor crystal material is put into the recess 21 having a circular cross section, and the substrate fixing body 2 having the substrate holder 3 mounted thereon is inserted into and fixed to the quartz closed tube 1. Then, the inside of the quartz closed tube is decompressed to a desired level to close the quartz closed tube. No. 1 opening is sealed.

The predetermined amount of the multi-source semiconductor crystal material means that when the quartz closed tube 1 is held so that the fan-shaped body portion 22 of the substrate fixing body 2 is located above when the multi-source semiconductor solution 7 is heated. As shown in FIG. 2 (A), the closed quartz tube 1 is rotated 180 degrees so that the substrate holder 3 is above the liquid surface of the multi-component semiconductor solution 7 and the fan-shaped portion 22 of the substrate fixing body 2 is located below. Then, as shown in FIG. 2B, the crystal substrate 5 is immersed in the multi-element semiconductor solution 7.

Using the liquid phase epitaxial growth apparatus as described above, liquid phase epitaxial growth of a multi-element semiconductor crystal on the surface of the crystal substrate 5 is performed as follows. A quartz closed tube 1 with a multi-source semiconductor crystal material (eg Hg, Cd, Te) and a crystal substrate (CdTe crystal plate) 5 sealed is placed in an electric furnace at 500 ° C.
Then, as shown in FIG. 2A, the multi-source semiconductor crystal material is liquefied to form a multi-source semiconductor solution (Hg, Cd, Te solution) 7.

Next, after the closed quartz tube 1 is cooled to a saturation temperature (480 ° C.) or lower, the closed quartz tube 1 is rotated 180 degrees, and FIG.
As shown in FIG. 2, the substrate holder 30 is turned upside down and the crystal substrate 5 is laid horizontally downward, so that the substrate is immersed in the multi-element semiconductor solution 7 and brought into contact with the multi-element semiconductor crystal (mixed crystal of HgTe and CdTe).
Are grown on the surface of the crystal substrate 5.

When the film has grown to a desired film thickness (for example, 50 μm), the quartz closed tube 1 is inverted to separate the multi-element semiconductor solution 7 from the crystal substrate 5 and stop the growth. Next, closed quartz tube 1
Is taken out of the electric furnace, cooled to room temperature, the quartz closed tube 1 is opened, the half of the substrate fixing body 2 is pulled out from the quartz closed tube 1, the substrate holder 3 is taken out, and the crystal substrate 5 is placed on the substrate holder 3
Remove from. The multi-source semiconductor crystal material is left in the recess 21 having a circular cross section.

Then, the crystal substrate to be subjected to liquid phase epitaxial growth is mounted on the substrate holder 3 and the substrate fixed body 2
Is inserted into the closed quartz tube 1, and a multi-element semiconductor crystal is grown by liquid phase epitaxial growth on the surface of the crystal substrate by the same procedure as described above.

In the substrate holder 3 of the liquid phase epitaxial growth apparatus for a multi-source semiconductor crystal according to the present invention, the surface opposite to the mounting surface of the crystal substrate 5 has a kamaboko-shaped convex surface 35. Therefore, when the quartz closed tube 1 is turned over 180 degrees to bring the crystal substrate 5 into contact with the multi-source semiconductor solution 7, the multi-source semiconductor solution 7 is on the upper side.

This prevents the multi-component semiconductor solution 7 from adhering to and remaining on the semi-cylindrical convex surface 35, so that the liquid level of the multi-component semiconductor solution 7 is constant during liquid phase epitaxial growth.

That is, the concentration of the multi-element semiconductor solution 7 in the portion in contact with the surface of the crystal substrate 5 becomes constant, and the composition of the multi-element semiconductor crystal that undergoes liquid phase epitaxial growth becomes constant. In addition,
The multi-element semiconductor crystal of the embodiment is Hg, Cd, Te, but the present invention is applied to other multi-element semiconductor crystal such as Pb, S, Se or Ga, As, P to obtain one having a constant composition. Of course, of course.

[0038]

As described above, according to the present invention, when the crystal substrate and the multi-component semiconductor solution are contacted / separated by the closed tube tipping method, and the multi-component semiconductor crystal is grown on the surface of the crystal substrate by liquid phase epitaxial growth, The substrate holder on which the substrate is mounted has a semi-cylindrical convex surface on the side opposite to the crystal substrate mounting surface, and the composition of the growing multi-source semiconductor crystal is always constant and stable. It has a practically excellent effect of high quality.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention with (A) being separated, and (B) being a sectional view of a substrate holder.

2 (A) and (B) are views for explaining the operation of the present invention.

FIG. 3 is a side sectional view of a conventional liquid phase epitaxial growth apparatus.

4 (A) and 4 (B) are views for explaining the operation of the conventional example.

[Explanation of symbols]

 1 Quartz closed tube 2 Substrate fixed body 3,30 Substrate holder 5 Crystal substrate 7 Multi-element semiconductor solution 21 Sectional circular recess 22 Fan-shaped body 24 Guide groove 31 Flat surface 32 Square recess 35 Kabama-shaped convex surface

Claims (1)

[Claims] 1. A crystal substrate and a multi-source semiconductor crystal material are sealed in a tube and heated, and the crystal substrate and the multi-source semiconductor solution are contacted / separated by a closed tube tipping method, and a multi-source semiconductor crystal is formed on the surface of the crystal substrate. Is a device for performing liquid phase epitaxial growth, which comprises a quartz closed tube (1) horizontally pivotally supported rotatably by 180 degrees, and a substantially cylindrical substrate fixing body (2) inserted into the quartz closed tube (1). ), A circular concave section (21) provided in a substantially central part of the substrate fixing body (2), and a rectangular concave part (21) into which the crystal substrate (5) is pushed into the central part of a flat surface (31) for setting. 32) and a substrate holder (3) in which the surface opposite to the flat surface (31) is formed into a semi-cylindrical convex surface (35), and the circular cross section concave recess (21) has a predetermined amount. Multi-source semiconductor solution
The substrate holder (3) has a function of a container for accommodating (7), and the crystal substrate (5) is horizontal and the kamaboko-shaped convex surface (35) is oriented toward the opening side. The substrate fixing body (2) is to be mounted in the recessed circular recess (21), and the top and bottom of the substrate holder (3) are inverted by rotating the quartz closed tube (1). A liquid phase epitaxial growth apparatus for a multi-element semiconductor crystal characterized by the above.