JPH0260226B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] The present invention is a substrate holding jig for forming a compound semiconductor crystal layer composed of Hg _1-x Cd _x Te etc. by liquid phase epitaxial crystal growth. A part of the center of the outer periphery of the cylinder is cut out in the direction of the center of the cylinder, and a substrate for crystal growth is held horizontally in a notched recess, and a melt for removing the melt surface film is placed on the outer periphery. The structure includes a melt material storage member having an outflow hole, and the melt material for crystal growth melted in the melt material storage member is passed through the melt outflow hole to form a surface film consisting of an oxide film or the like crystallized on the surface of the melt material. This is to prevent the occurrence of crystal defects due to adhesion of the melt surface film by leaving the melt remaining and flowing out onto the surface of the substrate for crystal growth.

[Industrial application field]

The present invention relates to improvements in a substrate holding jig for liquid phase epitaxial crystal growth, and particularly to a substrate holding jig suitable for liquid phase epitaxial growth of compound semiconductor crystals containing easily evaporable component elements.

Liquid phase epitaxial crystal growth is generally used to grow light-emitting devices, laser devices, or light-receiving devices using semiconductor crystals made of multiple elements, such as compound semiconductor crystals such as gallium arsenide (GaAs) and gallium-aluminum-arsenic (GaAlAs). It is used to form etc. In addition, in recent years, lead, tin, tellurium (Pb _1-x Sn _x Te) and easily evaporable
Mercury, cadmium, tellurium (Hg _1-x Cd _x
Using compound semiconductor crystals such as Te) as constituent materials,
It is well known that it is used to form photoelectric conversion elements such as infrared detection elements and infrared semiconductor laser elements.

In particular, the present inventors have already described a method for forming compound semiconductor crystals of mercury, cadmium, tellurium (Hg _1-x Cd _x Te), etc., containing a component element consisting of easily evaporable Hg, by liquid phase epitaxial growth. A proposed closed rotation liquid phase epitaxial crystal growth method is used.

In these liquid phase epitaxial crystal growth processes, it is necessary to form a crystal layer with a uniform composition ratio on a large crystal substrate so that a large number of devices can be formed from a single crystal substrate, and also to eliminate crystal defects. It is required to be able to easily form a crystal layer free of crystals.

For this reason, it is possible to prevent surface films such as oxide films that are formed on the surface of the melt material for crystal growth, which is one of the causes of crystal defects, from adhering to the substrate surface, and to easily form a defect-free crystal layer. There is a need for a substrate holding jig for liquid phase epitaxial crystal growth that can be formed.

[Conventional technology]

As shown in Figure 3, the jig used in the conventional closed rotation type liquid phase epitaxial crystal growth method, that is, the substrate holding jig, has an outer diameter and a predetermined length inscribed in a quartz ampoule, which will be described later. , e.g. quartz glass,
Alternatively, a notch recess 2 is formed by cutting out a part of the center of the outer circumference of a cylinder 1 made of a carbon material in the direction of the central axis A of the cylinder 1, and a part for crystal growth is provided between opposing wall surfaces in the notch recess 2. The structure is such that the substrate 3 is held horizontally.

During liquid phase epitaxial crystal growth, the notched recess 2 of the jig 11 is used as shown in the figure.
A substrate 3 for crystal growth made of CdTe, for example, is provided inside.
This substrate holding jig 11 and Hg _1-x weighed in advance to a predetermined composition ratio are held in a horizontally extending manner.
A crystal growth melt material 5 made of Cd _x Te is inserted into a quartz ampoule 4, and the substrate holding jig 11 is hermetically sealed so that it does not move inside while the inside is evacuated.

Thereafter, the quartz ampule 4 is placed in an epitaxial crystal growth furnace (not shown) and heated to a predetermined temperature higher than the crystal growth temperature to melt the crystal growth melt material 5 in the quartz ampule 4, and the quartz The ampoule 4 is rotated 180 degrees to bring the molten crystal growth melt material 5 into contact with the surface of the substrate 3, and the heating temperature is lowered to a predetermined crystal growth temperature to deposit Hg _1-x Cd _x Te on the substrate 3. A crystal layer consisting of is grown.

Further, when a crystal layer of a predetermined thickness is formed, the quartz ampoule 4 is turned over again by 180 degrees to return to its original state, thereby removing the melt material 5 on the substrate 3 and allowing the crystal growth to proceed. After stopping, the cooled quartz ampoule 4 is pulled out from inside the growth furnace and unsealed, and the substrate 3 on which the crystal layer made of Hg _1-x Cd _x Te is formed is taken out from the jig 11.

[Problem that the invention seeks to solve]

By the way, such a conventional substrate holding jig 11
In the method of performing liquid phase epitaxial crystal growth on the surface of the substrate 3 for crystal growth using
A quartz ampoule 4 filled with the crystal growth melt material 5 is placed together with the substrate holding jig 11 holding the crystal growth melt material 5.
When rotating 180 degrees and bringing the molten crystal growth melt material 5 into contact with the surface of the substrate 3, a surface film formed on the surface of the melt material 5, such as an oxide film, adheres to the surface of the substrate, Due to this, there was a drawback that defects occurred in the epitaxial crystal layer formed.

The occurrence of such defects not only occurs within the crystal layer, but also abnormal growth protrusions and pits occur on its surface, making it impossible to use it for device formation.

In order to eliminate the above-mentioned conventional drawbacks, the present invention removes a surface film such as an oxide film formed on the surface of the melt material for crystal growth on the jig itself that holds the substrate for crystal growth. An object of the present invention is to provide a novel substrate holding jig for liquid phase epitaxial crystal growth, which prevents the occurrence of crystal defects in a growing crystal layer due to adhesion of a surface film formed on a melt material to the substrate surface. This is the purpose.

[Means for solving problems]

In order to achieve the above object, the present invention holds a substrate for crystal growth horizontally in a notched recess formed by cutting out a part of the center of the outer periphery of a cylinder of a predetermined length in the direction of the center of the cylinder. At the same time, the jig has a structure in which a melt material storage member having a melt outflow hole for removing a melt surface film is provided in the outer peripheral portion in parallel therewith.

[Effect]

The substrate holding jig for liquid phase epitaxial crystal growth of the present invention horizontally holds the substrate for crystal growth provided in the notch recess, and
In parallel with this, a melt material storage member having a melt outflow hole for removing the melt surface film on the outer periphery is provided, so that the substrate for crystal growth is held,
If the jig with the melt material for crystal growth stored in the melt material storage member is inserted into a quartz ampoule and sealed, and the quartz ampoule is heated to melt the melt material, the melted melt material will be melted. It flows out from the outflow hole to the quartz ampoule side.

At this time, the surface film formed on the surface of the melt material, such as an oxide film, is dammed up by the melt outflow hole and prevented from flowing out.

Therefore, if the quartz ampoule is rotated 180 degrees in this state as before, only the melt material for crystal growth from which the surface film has been removed will come into contact with the substrate surface, and the surface film will not adhere to the substrate surface. It becomes possible to easily form an extremely well-grown crystal layer without the occurrence of crystal defects.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view of a main part showing an embodiment of a substrate holding jig for liquid phase epitaxial crystal growth according to the present invention.

In the figure, reference numeral 22 denotes a notch recess 23 which is a part of the center of the outer circumference of a cylinder of a specified length made of quartz glass or carbon material inscribed in a quartz ampoule and cut out in the direction of the center of the cylinder. A substrate 26 for crystal growth is held horizontally in the cutout recess 23, and a melt outflow hole 25 for removing the melt surface film is provided in parallel to the outer periphery. The jig has a structure in which the provided semicylindrical melt material storage member 24 is arranged in the shape shown in the figure.

The cylindrical jig main body 22 may be block-shaped or hollow.

Next, an example of use of the substrate holding jig 21 of the present invention having the above-described structure will be described.

First, as shown in FIG. 2, the substrate holding jig 21 is
A crystal growth substrate 26 made of, for example, CdTe is held horizontally in the cutout recess 23 .

Further, a semicylindrical melt material storage member 24 is provided with a melt outflow hole 25 on the outer periphery for removing the melt surface film.
Inside is Hg _1-x Cd _x Te weighed in advance to a predetermined composition ratio.
The melt material accommodating member 24 accommodates a crystal growth melt material 27 consisting of the notch recess 2.
3 as shown in the figure.

Thereafter, the substrate holding jig 21 is inserted into the quartz ampoule 28, the inside is evacuated, and the jig 21 is hermetically sealed so that it does not move inside.

Next, this quartz ampoule 28 is inserted into an epitaxial crystal growth furnace (not shown) and heated to a predetermined temperature slightly higher than the crystal growth temperature to melt the crystal growth melt material 27 within the quartz ampoule 28.

At this time, the crystal growth melt material 27 melted within the melt material storage member 24 is transferred to the melt outlet hole 2.
5 to the quartz ampoule 28 side, and at this time, the surface film formed on the surface of the melt material 27, such as an oxide film, is dammed up by the melt outflow hole 25, and the outflow is prevented.

Thereafter, the quartz ampoule 28 in this state is rotated 180 degrees in the same manner as before to bring the melt material 27 into contact with the surface of the substrate 26, and the heating temperature is lowered to a predetermined crystal growth temperature to deposit Hg ₁ on the substrate 26. _-x
By growing a crystal layer consisting of Cd _x Te,
It becomes possible to easily form a well-grown crystal layer on the substrate 26 without generating crystal defects due to surface film adhesion.

At this time, the surface film made of an oxide film or the like is prevented from flowing out and remains in the melt material storage member 24.

After the crystal growth is completed, the quartz ampoule 28 is turned 180 degrees to its original state and the melt material 2 on the substrate 26 is removed.
7 is removed and the temperature is lowered, and then the quartz ampoule 28 is pulled out from inside the growth furnace and unsealed, and the substrate holding jig 2 is removed.
A substrate 26 on which a crystal layer made of Hg _1-x Cd _x Te is formed is taken out from No. 1 .

In addition, in the above embodiment, the melt material storage member 24
The melt outflow hole 25 for removing the melt surface film provided in the melt material 27 has been described in the case of one hole, but if a plurality of holes, that is, a mesh-like hole is used, the removal effect of the surface film generated on the melt material 27 will be improved. Become bigger.

〔Effect of the invention〕

As is clear from the above description, according to the substrate holding jig for liquid phase epitaxial crystal growth according to the present invention, the melt material accommodating member disposed together with the substrate for crystal growth in the notch recess allows the substrate to be A surface film such as an oxide film formed on the surface of the crystal growth melt material that is melted to be in contact with the surface of the crystal growth substrate is removed, resulting in a clean crystal growth melt with no surface film on the substrate surface. Since only the material is subjected to growth, it has the excellent advantage that it is possible to easily form a well-grown crystal layer free from crystal defects caused by adhesion of surface films.

Therefore, it is extremely advantageous to apply not only to liquid phase epitaxial crystal growth of a crystal layer made of Hg _1-x Cd _x Te but also to liquid phase epitaxial crystal growth of this type of compound semiconductor crystal layer.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of a substrate holding jig for liquid phase epitaxial crystal growth according to the present invention;
FIG. 2 is a sectional view of a main part for explaining an example of use of the substrate holding jig for liquid phase epitaxial crystal growth according to the present invention, and FIG. 3 is a conventional substrate holding jig for liquid phase epitaxial crystal growth. FIG. 1 and 2, 21 is a substrate holding jig, 22 is a jig main body, 23 is a notch recess, and 24
2 is a melt material storage member, 25 is a melt outflow hole, and 2
6 is a substrate for crystal growth, 27 is a melt material, 28
indicates a quartz ampoule, respectively.

Claims (1)

[Scope of Claims] 1. A part of the center of the outer circumference of a cylinder having a predetermined length is cut out in the direction of the center of the cylinder.
A substrate holding jig for holding a substrate 26 for crystal growth horizontally and sealing it in a quartz ampoule together with a melt material for crystal growth, the notch recess 23 communicating with the substrate 26. A substrate holding jig for liquid phase epitaxial crystal growth, comprising: a melt material storage member 24 having a melt outflow hole 25 for removing a melt surface film on the outer periphery thereof.