JPH0536731A - Jig for growing liquid phase epitaxial crystal and method for manufacturing multi-element semiconductor crystal using the jig - Google Patents

Abstract

PURPOSE:To prevent crystal defects from occurring by the influence of the oxide film of a fused material concerning the title jig and the manufacturing method. CONSTITUTION:The title jig has a cut recess 3, where, for example, one part at the center of the periphery of a column is cut off in the direction of the center axis of the column. The jig holding a crystal growth substrate 4 in the recess 3 together with a melt material 5 into a quartz ampule 2 and an oxide film removing plate 8 is laid horizontally inside the cut recess 3 along the inwall of the quartz ampule 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jig for liquid phase epitaxial crystal growth and a method for producing a multi-element semiconductor crystal using the jig.

A multi-element semiconductor crystal composed of a plurality of compositional elements,
For example, one of the methods for growing a compound semiconductor crystal of gallium / arsenic, gallium / aluminum / arsenic, etc. on a crystal substrate is to bring a solution of these semiconductors as a solute into contact with the crystal substrate at a high temperature and then gradually increase the temperature. There is a method in which a lowered semiconductor crystal is deposited and grown on a substrate.

This method is generally called a liquid phase epitaxial crystal growth method, and is widely adopted as a method for growing a single crystal having high purity and good crystallinity, particularly in the field of semiconductor industry. In recent years, photoelectric conversion elements such as infrared detection elements and infrared semiconductor laser elements have been manufactured using compound semiconductor crystals such as lead, tin, tellurium, and mercury, cadmium, tellurium, etc. containing easily evaporative constituent elements as constituent materials. The above method has been used to do this.

In particular, when a multi-element semiconductor crystal containing easily vaporizable component elements is manufactured by liquid phase epitaxial growth, in order to prevent the solution concentration from changing due to evaporation, crystal growth is performed in a closed container such as a quartz ampoule. And the optimization of the method is being sought.

[0005]

2. Description of the Related Art An example of a conventional method for producing a multi-element semiconductor crystal by liquid phase epitaxial crystal growth will be described with reference to FIG. Reference numeral 1 is a liquid phase epitaxial crystal growth jig. This jig cuts a part of the center of the outer circumference of a cylinder made of, for example, quartz glass or carbon material and having an outer diameter inscribed in a quartz ampoule 2 and a predetermined length. It has a notched recessed portion 3 that is cut out, and is configured to horizontally hold the crystal growth substrate 4 horizontally across the opposing wall surfaces in the notched recessed portion 3.

During the liquid phase epitaxial crystal growth, a crystal growth substrate 4 made of CdTe is held horizontally in the notched recess 3 and the jig 1 and
A melt material 5 for crystal growth composed of Hg, Cd, and Te, which has been weighed in a predetermined composition ratio in advance, is placed in a quartz ampoule 2 as shown in the figure, and the quartz ampoule is hermetically sealed after exhausting the inside of the ampoule. Stop.

Thereafter, the quartz ampoule 2 is placed in an electric furnace (not shown) and heated to a predetermined temperature higher than the crystal growth temperature to melt the melt material 5 in the quartz ampoule 2 and rotate the quartz ampoule 2 by 180 °. Then, the melted melt material is brought into contact with the surface of the crystal growth substrate 4 and the heating temperature is lowered to a predetermined crystal growth temperature to thereby bring the crystal growth substrate 4 into contact.
A single crystal layer of Hg _1-x Cd _x Te is grown on top.

Next, when the single crystal layer having a predetermined thickness is formed, the quartz ampoule 2 is rotated again by 180 ° to remove the melt material on the crystal growth substrate 4 and stop the crystal growth. The quartz ampoule 2 is pulled out from the furnace while being gradually cooled, the quartz ampoule 2 is opened, and the substrate 4 on which the single crystal layer is formed is taken out.

[0009]

By the way, in the above-mentioned conventional method, when the inside of the quartz ampoule is evacuated to a vacuum and the melt material is melted by heating, it is melted by the influence of residual oxygen that cannot be exhausted. A slight oxide film is formed on the surface of the melt material.

When the quartz ampoule is rotated to bring the substrate for crystal growth into contact with the molten melt material with the oxide film formed on the surface of the molten melt material, the substrate for crystal growth is gradually dipped in the molten melt material. In doing so, there is a problem that a fragment of the oxide film adheres to the surface of the crystal growth substrate and a crystal defect occurs in the crystal-grown single crystal layer.

According to experiments conducted by the inventor, it has been found that crystal defects occur due to the influence of residual oxygen of about 0.2 ppm. The present invention was created to deal with such a problem, and an object thereof is to prevent occurrence of crystal defects due to the influence of an oxide film.

[0012]

A jig for liquid phase epitaxial crystal growth according to the present invention has a notched concave portion formed by cutting out a part of the center of the outer peripheral portion of a cylinder in the direction of the central axis of the cylinder. A jig for holding a substrate for crystal growth in a notched recess and enclosing it in a quartz ampoule together with a melt material, wherein an oxide film removal plate is laid horizontally in the notched recess along the inner wall of the quartz ampoule. Composed.

The method for producing a multi-source semiconductor crystal of the present invention using this jig for liquid phase epitaxial crystal growth comprises the step of vacuum-sealing the jig together with the crystal growth substrate and the melt material in the quartz ampoule. A step of horizontally supporting the quartz ampoule so that the cutout recess faces downward and melting the melt material by heating, and the oxide film removing plate is placed on the melt melt material before the crystal growth substrate. Rotating the quartz ampoule by 180 ° in a rotation direction so as to contact with the substrate, bringing the molten melt material into contact with the substrate for crystal growth to perform crystal growth, and rotating the quartz ampoule again by 180 ° to melt the melt. Preventing the melt material from coming into contact with the crystal growth substrate.

[0014]

In the liquid phase epitaxial crystal growth jig of the present invention, since the oxide film removing plate is horizontally provided in the notch recess along the inner wall of the quartz ampoule, this jig is used in accordance with the method of the present invention. When used, the following unique effects occur.

That is, when the quartz ampoule is rotated by 180 ° in such a rotating direction that the oxide film removing plate comes into contact with the molten melt material before the crystal growth substrate, the oxide film on the surface of the molten melt material is an oxide film. The removal plate does not interfere with the crystal growth substrate to prevent the crystal defects from occurring.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view of a jig for liquid phase epitaxial crystal growth showing a preferred embodiment of the present invention,
This jig 1 has a notched recess 3 formed by cutting out a part of the center of the outer peripheral part of a cylinder made of quartz glass in the direction of the central axis of the cylinder.
have.

In this embodiment, the crystal growth substrate 4 made of CdTe is supported by the substrate support base 6, and the substrate support base 6 is fitted into the groove 7 formed in the notched recess 3 on the opposite wall surface. As a result, the substrate is laid horizontally in the cutout recess 3.

The oxide film removing plate 8 made of quartz is likewise laid across the grooves 9 formed on the opposite wall surfaces of the notch recess 3. The shape of the groove 9 is set so that the horizontally-extending oxide film removing plate 8 is parallel to the central axis of the jig 1.

The jig 1 is a quartz having an inner diameter slightly larger than the outer diameter of the jig 1 with the crystal growth substrate 4, the substrate support 6 and the oxide film removal plate 8 set as described above. It is inserted into the ampoule 2. At this time, the melt material 5 together with the jig 1 is inserted into the quartz ampoule 2 so that the melt material is located in the notch recess 3. The constituent elements of the melt material 5 are Hg, Cd, and Te, and the composition ratio thereof is set according to the composition ratio of the multi-source semiconductor crystal to be manufactured.

Reference numeral 10 denotes a lid member for sealing the quartz ampoule 2, and the lid member 10 is made of quartz integrally with the exhaust pipe 11. After welding the lid member 10 to the end of the quartz ampoule 2, the quartz ampoule 2 is connected via the exhaust pipe 11.
A vacuum is drawn inside. After that, the quartz ampoule can be hermetically sealed by sealing the exhaust pipe 11 in the middle thereof, for example.

The process of liquid phase epitaxial crystal growth in this embodiment will be described with reference to FIG. First, the quartz ampoule 2 in which the crystal growth substrate 4 and the melt material 5 are enclosed together with the jig 1 is heated to a predetermined temperature higher than the crystal growth temperature in the crystal growth furnace, and shown in FIG. In this way, the melt material 5 in the quartz ampoule 2 is melted to form a melt material 5 '. At this time, due to the influence of oxygen remaining in the quartz ampoule 2, a slight oxide film 12 is formed on the surface of the molten melt material 5 '.

Next, as shown in FIG. 2B, the quartz ampoule 2 is rotated clockwise in the figure. In the cross section shown in FIG. 2A, the oxide film removing plate 8 is provided along the right wall surface of the quartz ampoule 2. When the quartz ampoule 2 is rotated, the jig 1, the crystal growth substrate 4 and the oxide film removal plate 8 in the quartz ampoule 2 are also rotated accordingly.

At this time, since the liquid surface of the molten melt material 5'maintains a horizontal surface, the oxide film 12 becomes the oxide film removing plate 8 '.
2B, it does not move to the right side of the oxide film removing plate 8 in FIG. 2B.

In this embodiment, since the step 8a is formed at the edge portion on the central axis side of the cylinder of the oxide film removing plate 8 toward the side opposite to the substrate 4, the oxide film 12 is effectively removed. Can be removed.

Then, the quartz ampoule 2 is rotated until the rotation angle becomes 180 °, and the molten melt material 5'is brought into contact with the crystal growth substrate 4 as shown in FIG. 2 (C). When the temperature in the furnace is lowered to a predetermined crystal growth temperature in this state, Hg _1-x Cd _x Te is formed on the surface of the crystal growth substrate 4.
The crystal layer 13 of is grown. At this time, since the oxide film of the melt material is not attached to the surface of the substrate 4 for crystal growth, which is a base material, there is no risk of crystal defects occurring in the crystal layer 13.

After that, when the crystal layer 13 having a predetermined thickness is formed, as shown in FIG. 2D, the quartz ampoule 2 is rotated again by 180 ° so that the molten melt material 5'is converted into a crystal growth substrate. The crystal growth is stopped by making no contact with No. 4.

Finally, although not shown, the quartz ampoule 2 is pulled out from the furnace while being gradually cooled, and the quartz ampoule 2 is removed.
And the crystal growth substrate 4 on which the crystal layer 13 is formed is removed from the substrate support base 6.

According to this embodiment, defects are less likely to occur in the crystal layer, so that the manufacturing yield is greatly improved when a large number of infrared light receiving elements or the like are manufactured using a large-sized crystal growth substrate.

[0029]

As described above, according to the present invention,
When manufacturing a multi-element semiconductor crystal using a jig having a specific structure, it is possible to prevent the occurrence of crystal defects due to the influence of the oxide film.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a jig for liquid phase epitaxial crystal growth showing a preferred embodiment of the present invention.

FIG. 2 is an explanatory diagram of a process of liquid phase epitaxial crystal growth.

FIG. 3 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

1 Jig for liquid phase epitaxial crystal growth 2 quartz ampoule 3 Notch recess 4 Crystal growth substrate 5 Melt material 5'Melted melt material 8 Oxide film removal plate

Claims (4)

[Claims] 1. A notch recess (3) is formed by cutting out a part of the center of the outer periphery of the cylinder in the direction of the central axis of the cylinder, and a crystal growth substrate (4) is held in the notch recess. Melt material
A jig for enclosing the quartz ampoule (2) together with (5), the cutout recess along the inner wall of the quartz ampoule (2).
A jig for liquid phase epitaxial crystal growth, characterized in that an oxide film removing plate (8) is horizontally installed inside (3). 2. A step (8) is formed on an edge of the oxide film removing plate (8) on the central axis side of the cylinder toward the side opposite to the substrate (4).
The jig for liquid phase epitaxial crystal growth according to claim 1, wherein a) is formed. 3. A method for producing a multi-source semiconductor crystal using the jig for liquid phase epitaxial crystal growth according to claim 1 or 2, wherein the jig (1) comprises the substrate (4) for crystal growth and The step of vacuum-sealing the quartz ampoule (2) together with the melt material (5), the quartz ampoule (2) is horizontally supported so that the cutout recess (3) faces downward, and the melt is heated by heating. material
(5) is melted, and the quartz ampoule is rotated in a rotating direction such that the oxide film removal plate (8) comes into contact with the molten melt material (5 ′) before the crystal growth substrate (4). Rotating 180 °, bringing the molten melt material (5 ′) into contact with the crystal growth substrate (4) for crystal growth, and rotating the quartz ampoule (2) 180 ° again to melt the molten melt material. (5 ') is prevented from coming into contact with the crystal growth substrate (4). 4. The crystal growth substrate (4) is made of CdTe, and the constituent elements of the melt material (5) are Hg, Cd, and T.
The method for producing a multi-source semiconductor crystal according to claim 3, wherein the method is e.