JPS634626A - Substrate holding jig for liquid phase epitaxial crystal growth - Google Patents

Abstract

PURPOSE:To avoid crystal defects caused by adhesion of the surface film of a melt material for crystal growth melted in a melt material housing member is made to flow onto the surface of a substrate while the surface film composed of an oxide film or the like formed on the surface of the melt material by crystallization is being left from a melt flow outlet. CONSTITUTION:A melt material 27 melted in a melt material housing member 24 is made to flow into a quartz ampule 28 from a melt flow outlet 25. At that time, a surface film composed of an oxide film or the like formed on the surface of the melt material 27 is dammed up by the melt flow outlet 25 and its flowing-out is blocked. After that, the quartz ampule 28 in this state is turned 180 degrees to contact the surface of a substrate 26 with the melt material 27 and, at the same time, the heating temperature is lowered to a predetermined crystal growth temperature so as to make a crystal layer composed of an Hg1-xCdxTe layer grow on the substrate 26. With this constitution, an excellent crystal growth layer which is free from crystal defects created by the adhesion of the surface film can be formed easily on the substrate 26.

Description

[Detailed Description of the Invention] [Summary] The present invention is a substrate holding jig for forming a compound semiconductor crystal layer made of Hg+-xCdxTe etc. by liquid phase epitaxial crystal growth. A substrate for crystal growth, which is provided in a notched recess in which a part of the center of the outer periphery is cut out in the direction of the center of the cylinder, is held horizontally, and a melt outflow hole for removing the melt surface film is provided in the outer periphery. The melt material for crystal growth melted in the melt material containing member is passed through the melt outflow hole leaving a surface film of crystallized oxide film etc. on the surface of the melt material. This is made to flow out onto the surface of the substrate for crystal growth, thereby preventing the occurrence of crystal defects due to the adhesion of the melt surface film.

[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 generally involves semiconductor crystals consisting of multiple compositional elements, such as gallium arsenide (GaAs),
Compound semiconductor crystals such as gallium-aluminum-arsenic (GaA7As) are used as constituent materials to form light-emitting elements, laser elements, light-receiving elements, and the like. In recent years, lead, tin, tellurium (Pb, -xSnx
Mercury, cadmium, tellurium (Hgl) with a narrow energy gap, including component elements consisting of Te) and easily evaporable Hg.
It is well known that compound semiconductor crystals such as CdxTe) are used as constituent materials to form photoelectric conversion elements such as infrared detection elements and infrared semiconductor laser elements.

In particular, as a method for forming compound semiconductor crystals of mercury, cadmium, tellurium (Hgl-xCdx Te), etc. containing a component element consisting of easily evaporable Hg by liquid phase epitaxial growth, the hermetic sealing method already proposed by the present inventors has been proposed. A rotary liquid phase epitaxial crystal growth method is used.

In these liquid phase epitaxial crystal growth processes, it is necessary not only to form a crystal layer with a uniform composition ratio on a large substrate to be crystallized so that a large number of elements can be formed from a single crystal substrate, but also to prevent crystal defects. It is required that it be possible to easily form a crystal layer with no crystalline structure.

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.

C. Prior Art] 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 that is inscribed in a quartz ampoule, which will be described later. A cylinder 1 of a predetermined length made of quartz glass or carbon material, for example, has a notch recess 2 formed by cutting out a part of the center of the outer periphery in the direction of the central axis A of the cylinder l. The substrate 3 for crystal growth is held horizontally between opposing wall surfaces.

During liquid phase epitaxial crystal growth, for example, Cd
A substrate 3 for crystal growth made of Te is held horizontally on a rack, and this substrate holding jig 11 and a melt material 5 for crystal growth made of Hg, xCdxTe, weighed in advance to a predetermined composition ratio. Both are inserted into a quartz ampoule 4, and with the inside evacuated, the substrate holding jig 11 is hermetically sealed so that it does not move inside. .

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, 4 is rotated 180 degrees, and the crystal growth melt material 5 is melted on the surface of the substrate 3.
At the same time, the heating temperature is lowered to a predetermined crystal growth temperature to grow a crystal layer made of Ilg and xCdxTe on the substrate 3.

Further, when a crystal layer of a predetermined thickness is formed, the quartz ampoule 4 is reversed 180 degrees counter-axis again to return to its original state, thereby removing the melt material 5 on the substrate 3 and causing crystal growth. After that, the cooled quartz ampoule 4 is pulled out from inside the growth furnace and unsealed, and the FIgl is removed from the jig 11.
-xCdx Group f in which a crystal layer consisting of Te is formed! 3
is being taken out.

[Problem that the invention seeks to solve]

By the way, in a method of performing liquid phase epitaxial crystal growth on the surface of the substrate 3 for crystal growth using such a conventional substrate holding jig 11, the substrate holding jig 11 holding the substrate 3 and the crystal growth When the quartz ampoule 4 containing the melt material 5 for crystal growth is rotated 180 degrees to bring the molten melt material 5 for crystal growth into contact with the surface of the substrate 3, an oxide film etc. formed on the surface of the melt material 5 is removed. There is a drawback that a surface film adheres to the surface of the substrate, which causes defects 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 of oxidized pus, etc. 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 that 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. That is.

[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.

[For production]

The substrate holding jig for liquid phase epitaxial crystal growth of the present invention holds the substrate for crystal growth provided in the notch recess in a horizontal manner, and also has a melt surface on the outer periphery in parallel with this. Since a melt material accommodating member provided with a melt outflow hole for film removal is provided, the jig holds the substrate for crystal growth and stores the melt material for crystal growth in the melt material accommodating member. is inserted into and sealed in a quartz ampoule, and the quartz ampoule is heated to melt the melt material, and the melted melt material flows out from the melt outflow hole toward 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, in this state, the quartz ampoule is
By rotating the substrate by 80 degrees, only the melt material for crystal growth from which the surface film has been removed is brought into contact with the substrate surface, resulting in an extremely well-grown crystal layer free from crystal defects caused by the adhesion of the surface film on the substrate. can be easily formed.

〔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 opening recess 23, and a melt outflow hole 25 for removing the melt surface film is provided at the outer periphery in parallel with this. The jig has a structure in which a semi-cylindrical melt material storage member 24 is arranged in the shape shown in the figure.

Note that 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, a substrate 26 for crystal growth made of, for example, CdTe is held horizontally in the cutout recess 23 of the substrate holding jig 21.

Further, a crystal growth melt material 27 made of Hg+-xCdx Te weighed in advance at a predetermined composition ratio is stored in a semi-cylindrical melt material storage member 24 having a melt outflow hole 25 for removing a melt surface film on the outer periphery. The melt material storage member 24 is disposed within the opening recess 23 as shown in the figure.

After that, the substrate holding jig 21 is placed in a quartz ampoule 28.
After the jig 21 is inserted into the interior and the interior is evacuated, 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 flows out from the melt outflow hole 25 to the quartz ampoule 28 side, and the oxide film etc. formed on the surface of the melt material 27 at this time flows out. The surface film is the melt outflow hole 2
5, it is dammed and the outflow is prevented.

Thereafter, the quartz ampoule 28 in this state is
By rotating the substrate 26 by 80 degrees and bringing the melt material 27 into contact with the surface of the substrate 26, the heating temperature is lowered to a predetermined crystal growth temperature to grow a crystal layer consisting of Hg, XCd, and Te on the substrate 26. 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 returned to its original state.
80 degrees anti-axis inversion base f! The melt material 27 on the substrate holder 26 is removed and the temperature is lowered, and then the quartz ampoule is pulled out from inside the growth furnace and opened, and Hg+-xCdx is removed from the substrate holding jig 21.
The substrate 26 on which the crystal layer made of Te is formed is taken out.

In the above embodiments, the melt outflow hole 25 for removing the melt surface film provided in the melt material storage member 24 was explained as a single hole, but it may be formed as a plurality of holes, that is, a mesh-like hole. , the effect of removing the surface film formed on the melt material 27 becomes greater.

〔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 storage member disposed together with the crystal growth substrate in the notch recess allows the crystal growth target to be A surface film such as an oxide film formed on the surface of the melt material for crystal growth that is melted to be brought into contact with the surface of the growth substrate is removed, resulting in a clean melt material for crystal growth with no surface film on the surface of the substrate. It has the excellent advantage that a well-grown crystal layer without crystal defects caused by adhesion of a surface film can be easily formed because only the crystals are subjected to growth.

Therefore, it is extremely advantageous not only for liquid phase epitaxial crystal growth of a crystal layer made of Hg+-xCdx Te but also for liquid phase epitaxial crystal growth of this type of compound semiconductor crystal layer.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing an embodiment of the substrate holding jig for liquid phase epitaxial crystal growth according to the present invention, and Fig. 2 shows an example of use of the substrate holding jig for liquid phase epitaxial crystal growth according to the present invention. FIG. 3 is a sectional view of a main part for explaining a conventional substrate holding jig for liquid phase epitaxial crystal growth. 1 and 2, 21 is a substrate holding jig, 22 is a jig main body, 23 is a notch recess, 24 is a melt material storage member, 25 is a melt outlet hole, 26 is a substrate for crystal growth, 27 is the melt material, 28 is the quartz ampoule, Fig. 1 Book - Beginning of the fk example - fifj Pf? Vinegar 2nd figure 11fl'J'e 2 Pubi e month! 13 Nemi etc. (2C
Figure 3

Claims (1)

[Scope of Claims] A substrate for crystal growth (26) is horizontally suspended in a cutout recess (23) 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. A substrate holding jig which is held in a quartz ampoule together with a melt material for crystal growth, the notch recess (23) communicating with the substrate (26), and having a melt surface on the outer periphery. A substrate holding jig for liquid phase epitaxial crystal growth, comprising a melt material storage member (24) provided with a melt outflow hole (25) for film removal.