JPH01224294A - Liquid phase epitaxial growing process and apparatus therefor - Google Patents

Abstract

PURPOSE:To provide the title process and apparatus so designed that a protective plate is retreated, by its own weight, from the position facing a substrate at the point of epitaxial growth and a melt is brought into contact with said substrate to carry out growth, thereby preventing the component constituting said substrate from evaporation out of the surface of the epitaxial growth substrate. CONSTITUTION:An upper part supporting member 21A and a substrate-holding channel 24 are fitted with an epitaxial growth substrate 22 made of CdTe and a supporting plate 28. Along with this, a protective plate 23 with the same composition as that of the substrate 22 and a supporting plate 27 are installed facing in close proximity to said substrate into a protective plate-holding channel 25. Furthermore, a melt for epitaxial growth 26 is put in an ampul 9. Concurrently with this, the upper part supporting member 21A and lower part supporting member 21B are fixed using a pin, and the ampul 9 is sealed with an inner tube 10 inserted. In this state, the melt 26 is heated and melted. Since the protective plate 23 is installed in close proximity to the substrate 22, the evaporation space for Cd atoms. is narrowed to effect saturation of the Cd atoms. within the narrow facing space between said substrate 22 and the protective plate 23, thus preventing the Cd from evaporation from said substrate.

Description

[Detailed Description of the Invention] [Summary] Regarding a liquid phase epitaxial growth method and an apparatus thereof, the present invention relates to a liquid phase epitaxial growth method and an apparatus thereof, which prevents components constituting the substrate from evaporating from the surface of the epitaxial growth substrate due to heating when melting a melt for epitaxial growth. A liquid phase epitaxial growth apparatus comprising: a support member having a space for accommodating a molten epitaxial growth melt and holding an epitaxial growth substrate on an opposing surface; and an ampoule accommodating the support member; A protective plate having the same composition as the substrate and preventing evaporation of components of the substrate is installed on the surface facing the substrate for epitaxial growth, and when the ampoule is rotated and the substrate is brought into contact with the melt to perform epitaxial growth, The protection plate is slid and retracted by its own weight from a position facing the substrate for epitaxial growth, and the melt for epitaxial growth is brought into contact with the substrate and grown.

[Industrial application field]

The present invention relates to a liquid phase epitaxial growth method and an apparatus therefor, and more particularly to a liquid phase epitaxial growth method and an apparatus therefor which prevent components constituting the substrate from evaporating from the surface of the epitaxial growth substrate when melting the epitaxial growth melt.

Water, cadmium, and tellurium crystals with narrow energy band gears are used for infrared detection elements and photoelectric conversion elements such as infrared laser elements.

When such Hg+-x Cdx Te crystals are epitaxially grown on a cadmium tellurium (CdTe) substrate, since mercury is an element that evaporates easily, an ampoule with a sealed structure is used to prevent the evaporation of the mercury and the molten Hg+-
The tilted liquid phase epitaxial growth method and apparatus for forming an epitaxial layer on a substrate by bringing a melt of x Cdx Te into contact with the substrate are popular due to the fact that the method and apparatus are hour wheels and the composition controllability of the epitaxial layer is good. It is widely used.

In such an epitaxial growth method and an apparatus thereof, a liquid phase epitaxial growth method and an apparatus thereof are desired in which components constituting the substrate are not evaporated from the surface of the substrate due to heating during melting of the epitaxial growth material. ing.

[Conventional technology]

FIG. 4 is a sectional view of an apparatus used in a conventional liquid phase epitaxial growth method, and FIG. 5 is a sectional view taken along line 1'/-rV' in FIG.

As illustrated in FIGS. 4 and 5, the conventional liquid phase epitaxial growth method uses CdT for epitaxial growth.
an upper support member 5 made of quartz, having a groove 3 for holding the substrate 1 of e and a support plate 2 made of quartz that supports the substrate 1; A lower support member 8 having a groove 3 for holding the above-described CdTe substrate 1 and support plate 2, and a space 7 for accommodating the epitaxial growth melt 6, these upper and lower support members 5 and 8, and a growth substrate t7i1. An apparatus consisting of an ampoule 9 which contains a melt 6 for epitaxial growth and then evacuates and seals the ampoule 9 is used.

The substrate l is inserted onto the support plate 2 into the groove 3 formed in the upper support member 5 and the lower support member 8, and the upper support member 5 and the lower support member 8 are fixed with the fixing pins (Fig. (not shown), the epitaxial growth melt 6 is inserted into the ampoule 9 in the space 7 of the support member 8 with the epitaxial growth melt 6 sandwiched between suitable semicircular melt storage containers, and then the inside of the ampoule 9 is inserted into the ampoule 9. After the tube 10 is inserted and the ampoule 9 is evacuated, one end A of the ampoule is sealed by welding.

After inserting the epitaxial growth apparatus into a furnace core tube in a heating furnace, the temperature of the heating furnace is raised to melt the epitaxial growth melt 6, and then the ampoule 9 is
After rotating the substrate 1 in the direction of the arrow B to bring the substrate 1 into contact with the melt 6 for epitaxial growth, the temperature of the heating furnace is lowered to form epitaxial crystals on the substrate.

[Problem to be solved by the invention]

However, in the conventional liquid phase epitaxial growth method,
When the melt for epitaxial growth is heated, the Cd atoms constituting the substrate are more easily evaporated than the substrate surface, so there is a risk of evaporation, and this evaporation causes the problem that the surface of the substrate becomes uneven.

When an epitaxial layer is formed on such an uneven substrate, the surface of the formed epitaxial layer also becomes uneven, and there is a problem that an epitaxial layer having a smooth plane cannot be obtained.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a liquid phase epitaxial growth method and an apparatus therefor, which prevent component elements constituting the substrate from evaporating from the surface of the substrate during heating of a melt for epitaxial growth.

[Means to solve the problem]

The epitaxial growth method of the present invention which solves the above problems is a liquid phase epitaxial growth method comprising a support member having a space for accommodating a melt for epitaxial growth and holding a substrate for epitaxial growth on opposing surfaces, and an ampoule for accommodating the support member. A protective plate, which faces the epitaxial growth substrate and has the same composition as the substrate and prevents evaporation of the components of the substrate, is installed on the opposite surface of the support member of the apparatus, and the ampoule is rotated to place the substrate into the melt. At the time of contact and epitaxial growth, the protection plate is slid and retracted by its own weight from the position facing the epitaxial growth substrate, and the epitaxial growth melt is brought into contact with the substrate and grown.

Further, in the epitaxial growth apparatus of the present invention, a protective plate facing the epitaxial growth substrate is held on the opposing surface of the support member, and has the same composition as the substrate and prevents components of the substrate, and when the ampoule is rotated, the protective plate Provide a protective plate holding groove that can be separated from the board by its own weight and retracted.

[For production]

In the epitaxial growth method of the present invention, by arranging a substrate and a protective plate having the same composition opposite to the substrate and placing them close to each other, Cd, which is a constituent element of the substrate, is evaporated from the substrate when the melt for epitaxial growth is heated. This creates a minute space in which Cd atoms are saturated, and this minute saturated space prevents easily evaporable Cd atoms from evaporating from the substrate, thereby preventing the substrate from becoming uneven. do.

Further, in the apparatus of the present invention, a protective plate is held on the above-mentioned support member, and a groove is provided so that the protective plate can be retracted from the substrate surface by its own weight during epitaxial growth, so that the protective plate can be retracted from the substrate surface during epitaxial growth.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail using the drawings.

FIG. 1 is a sectional view showing the structure of an embodiment of the epitaxial growth apparatus of the present invention, and FIG. An explanatory diagram of the operating state of the device, from Figure 3 (a) to Figure 3 (C)
FIG. 3 is an explanatory diagram of the operating state of the device in a cross-sectional view taken along the line nn'' in the figure.

Figure 1, Figure 2 (a) to Figure 2 (C), and Figure 3
As shown in FIG. 3 fC1 from FIG. Protective plate 2 with the same composition as 22
3, and a support plate 22 that supports the protection plate 23 is installed.

A protective plate holding groove 25 into which the protective plate 23 and the supporting plate 27 described above are inserted is provided on the opposing surface of the upper supporting member 21A of the supporting member 21. The dimension β of this groove 25 is the dimension of the epitaxial growth substrate 22! The ampoule 9 is formed to have a wider dimension and is structured to slide within the protective plate holding groove 25 under its own weight when the ampoule 9 is rotated during epitaxial growth.

The operation of forming an epitaxial layer on a substrate using the apparatus of the present invention will be described.

First, as shown in FIG. 1, the epitaxial growth substrate 22 made of CdTe and the support plate 28 are installed in the substrate holding groove 24 of the upper support member 21A, and the epitaxial growth substrate 22 and the support plate 28 are placed in the protection plate holding groove 25 in close opposition to the substrate vi 22. Then, a protection plate 23 and a support plate 27 having the same composition as the substrate 22 are installed.

Further, the epitaxial growth melt 26 is accommodated in the ampoule 9, and the upper support member 21A and lower support member 21B are fixed using a bottle (not shown), and the inner tube 10 is
The ampoule 9 is sealed with the ampoule 9 inserted.

In this state, as shown in FIG. 2(a) and FIG. 3(al), the epitaxial growth melt 26 is heated and melted. Cd atoms evaporate, but since the protection plate 23 having the same composition as the substrate 22 is installed close to it, the evaporation space for the Cd atoms is narrowed, and the evaporation space between the substrate 22 and the protection plate 23 is narrow. The Cd atoms become saturated, preventing evaporation of Cd from the substrate 22, so that no unevenness occurs on the surface of the substrate 22, and the epitaxial layer formed thereon also has a flat crystal.

Next, rotate 90'' in the direction of arrow C to bring it into the state shown in FIG. 2 (bl) and FIG. 3 (b). Then, the protective plate holding groove 25 and the Groove 2
Since the width dimensions of 4 are different, the protective plate 23
slides within the holding groove 25 under its own weight, and is separated from the opposing position of the epitaxial growth substrate 2 by a predetermined distance.

Next, move the ampoule 9 further in the direction of the arrow in FIG. 2(C).
Then rotate the substrate 22 by 90'' as shown in FIG. 3(C).
A melt 26 for epitaxial growth is brought into contact with the molten epitaxial growth melt 26 .

During this rotation, the protection plate 23 and its support plate 28 slide and move within the protection plate holding groove 25, so that the protection plate 23 is not displaced from the position facing the substrate 22 and does not interfere with epitaxial growth. Also, the melt 2 in which the protective plate 23 is melted
However, the composition of the protection vi 23 is the same as that of the epitaxial growth substrate 22, and the composition of the epitaxial growth melt 26 before melting is adjusted in advance by the amount that the components of the protection plate 23 melt into. If the melt is formed by weighing the melt, the composition of the epitaxial layer to be grown will not change due to the protection plate 23 melting into the melt.

In this way, even if the temperature of the substrate rises during the process of melting the epitaxial growth melt 26, a protection plate having the same composition as the substrate will be placed close to the substrate, and the components of the substrate will evaporate in the microspace created by this protection plate. is in a saturated state, the evaporation of the components constituting the substrate is suppressed more than the substrate, no unevenness is generated on the substrate, and an epitaxial layer with a flat surface is obtained.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, easily evaporable elements are not evaporated from the surface of the substrate during epitaxial growth (this makes the surface of the substrate smooth, so that no The epitaxial layer also has the effect of obtaining a high-quality epitaxial layer having a smooth surface.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the apparatus used in the method of the present invention, Figure 2 (
18) to FIG. 3(C) are explanatory diagrams of the operation of the apparatus of the present invention, and FIG. 4 is an explanatory diagram of the operation of the apparatus of the present invention. FIG. 5 is a cross-sectional view of the apparatus used in the method, taken along the line IV-■" in FIG. 4. In the figure, 7 is a space, 9 is an ampoule, 10 is an inner tube, 21 is a support member, 21A is an upper support member, 21B is a lower support member, 22
23 is a substrate for epitaxial growth, 23 is a protection plate, 24 is a groove for holding the substrate, 25 is a groove for holding the protection plate, 26 is a melt for epitaxial growth, and 27 and 28 are support plates. 1 movement of unexploded g death (Fig. 2 IQ)
Figure (e) Ju5 Ashi +-: I"fl-・戊1-#Menkoku Figure 4 O4 area ^ IV-I7'Azusa"isha Figure Figure 5

Claims (2)

[Claims] (1) A support member (21) having a space for accommodating an epitaxial growth melt (26) and holding an epitaxial growth substrate (22) on an opposing surface;
In a liquid phase epitaxial growth apparatus comprising an ampoule (9) containing a A protective plate (23) for preventing evaporation of components is installed, and when the ampoule is rotated and the substrate (22) is brought into contact with the melt (26) for epitaxial growth, the protective plate (23) is attached to the substrate. (22) An epitaxial growth method characterized in that the epitaxial growth melt (26) is brought into contact with the substrate (22) and grown by sliding the substrate (22) away from the facing position by its own weight. (2) A support member (21) having a space for accommodating an epitaxial growth melt (26) and holding an epitaxial growth substrate (22) on an opposing surface;
A liquid phase epitaxial growth apparatus comprising an ampoule (9) containing an epitaxial growth substrate (
holding a protective plate (23) for preventing evaporation of components of the substrate with the same composition as the substrate facing the substrate (22), and rotating the ampoule to separate the protective plate (23) from the substrate (22); An epitaxial growth apparatus characterized by having a protective plate holding groove (25) that can be retracted by its own weight.