JPH01219095A - Liquid phase epitaxial growth device - Google Patents

Abstract

PURPOSE:To prevent abnormal growth from being generated in the peripheral part of an epitaxial substrate by providing a melt reservoir between the inner wall of an ampule and the outer wall of an inner pipe and also providing a melt outflow pipe reaching the melt reservoir from the groove of a clamping jig. CONSTITUTION:A melt outflow pipe 19 is provided between the outer wall of an inner pipe 16 and the inner wall of an ampule 17 from the end part of the groove 13 for fixing a supporting plate of a clamping jig 15. A substrate 11 is provided on the supporting plate 12 and this supporting plate 12 is pinched by the groove 13 for the jig 15 and melt forming material 20 is introduced into the ampule 17. After sealing the end part, the ampule 17 is heated at 500 deg.C in a heating over to melt the material 20 and the device is rotated at 180 deg.. In this case, an epitaxial layer is formed on the substrate 11 and the excess melt on the substrate 11 flows out to a melt reservoir 18. Since only the necessary lower-limit melt remains on the substrate 11, the abnormal growth of the epitaxial layer is prevented from being generated in the peripheral part of the substrate.

Description

[Detailed Description of the Invention] [Summary] Regarding a liquid phase epitaxial growth apparatus, the purpose is to prevent abnormal growth of an epitaxial layer in the periphery of an epitaxial growth substrate, and a support plate that holds an epitaxial growth substrate is sandwiched. a fixing jig having a groove and a recess for accommodating a melted epitaxial growth melt at a position facing the substrate;
It consists of an inner tube for preventing positional fluctuation of the fixing jig, and an ampoule enclosing the fixing jig and the inner tube, and the ampoule is rotated to bring the melt for epitaxial growth molten onto the substrate into contact with the substrate. An apparatus for growing an epitaxial layer on a substrate, wherein a melt reservoir is provided between the inner wall of the ampoule and the outer wall of the inner tube, and the melt reservoir is provided in the fixing jig through an end of a groove of the fixing jig. Provide a melt outflow pipe,
During epitaxial growth in which the melt is brought into contact with the substrate, excess melt is guided into the melt reservoir through the melt outflow pipe.

[Industrial Field of Application] The present invention relates to a liquid phase epitaxial growth apparatus, and particularly to an apparatus that prevents abnormal growth of an epitaxial layer in the periphery of an epitaxial growth substrate.

Compound semiconductor crystals such as mercury-cadmium-tellurium (Hgl-XCdX Te), which have a narrow energy band gap, are used for infrared detection elements and photoelectric conversion elements such as infrared laser elements.

When such Hgl-yt Cdx Te crystals are epitaxially grown on a cadmium telluride (CdTe) substrate, since mercury is an element that evaporates easily, an ampoule with a sealed structure is used to prevent the evaporation of mercury and to prevent the molten mercury from evaporating. Hg,
A tilted liquid phase epitaxial growth apparatus, which forms an epitaxial layer on a substrate by bringing an XCdX Te melt into contact with the substrate, is widely used because the apparatus has a simple structure and the composition of the epitaxial layer can be easily controlled.

[Conventional technology]

Fig. 6 is a cross-sectional view of a conventional liquid phase epitaxial growth apparatus, Fig. 7 is a cross-sectional view along the vr-vr' line in Fig. 6 before epitaxial growth, and Fig. 8 is a cross-sectional view of a conventional liquid phase epitaxial growth apparatus. It is a diagram rotated by 180 degrees, and is a diagram at the time of epitaxial growth.

As shown in FIGS. 6, 7, and 8, the conventional liquid phase epitaxial growth apparatus has a groove 3 that sandwiches a support plate 2 that holds an epitaxial growth substrate 1, and has grooves 3 that sandwich a support plate 2 that holds an epitaxial growth substrate 1. It consists of a cylindrical fixing jig 6 made of quartz having a recess 5 for accommodating the epitaxial growth melt 4, and an ampoule 8 enclosing the fixing jig 6 together with an inner tube 7.

Then, the substrate 1 is installed on the support plate 2, the support plate 2 is installed in the groove 3 of the fixing jig 6, and the fixing jig in which the substrate is installed is placed on the opposite side facing the substrate. , cadmium, and tellurium, and is sealed in an ampoule 8 together with an inner tube 7 with a melt-forming material 4 for epitaxial growth inserted therein.

Next, the ampoule 8 is placed in a furnace core tube (not shown) in a heating furnace.
the ampoule 8 is heated to melt the melt-forming material 4 within the ampoule.

Next, the ampoule 8 is rotated 180 degrees in the six directions of the arrow, the epitaxial growth substrate 1 is brought into contact with the molten epitaxial growth melt 4, and the temperature of the melt 4 is lowered by lowering the temperature of the heating furnace to correspond to the lowered temperature. An epitaxial layer was deposited and formed on a substrate by contacting the substrate with a saturated melt having a saturated vapor pressure.

[Problem to be solved by the invention]

However, the above-described apparatus has a problem in that the epitaxial layer 9 grows abnormally in the periphery of the epitaxial growth substrate 1, as shown in FIG.

The reason for this is that the amount of solute in the melt that is diffused into a unit area of the substrate at the periphery of the substrate 1, that is, at the boundary with the support plate 2 or the boundary with the fixing jig 6, and which contributes to epitaxial growth, is If we estimate the amount of solute diffused into a unit area of the substrate at the center of the substrate 1 and contributing to epitaxial growth per unit area of the substrate 1, the amount of solute diffused into the center of the substrate 1 will be larger than the amount diffused into the center of the substrate 1. This is because the amount of diffusion becomes larger. That is, this is because the amount of solute that contributes to epitaxial growth is greater at the edges than at the center. This tendency occurs when the melt 4 on the substrate 1 is in contact with the substrate.
The larger the depth dimension 2 is, the larger the value is.

When forming an infrared sensing element, it is desirable that the epitaxial layer has a uniform thickness over the entire surface of the substrate in order to improve workability such as mask alignment. A step is taken to cut and remove that portion, which requires extra man-hours and also reduces the effective area of the epitaxial layer for forming elements.

The present invention eliminates the above-mentioned problems and reduces the amount of epitaxial growth melt supplied onto the substrate to the necessary minimum when forming an epitaxial layer on the substrate by rotating the ampoule and bringing the epitaxial growth melt into contact with the substrate. Hold,
It is an object of the present invention to provide a liquid phase epitaxial growth apparatus in which the dimension in the depth direction of the melt contacting the substrate below the substrate is reduced and abnormal growth of an epitaxial layer in the peripheral area of the substrate is prevented.

[Means to solve the problem]

A liquid phase epitaxial growth apparatus according to the present invention which achieves the above object has an epitaxial growth substrate 1 as shown in FIG.
A fixing jig 15 is provided with a groove 13 for sandwiching a support plate 12 holding the substrate 1, and has a recess 14 for accommodating the melt 20 for epitaxial growth at a position facing the substrate, and prevention of positional fluctuation of the fixing jig 15. It consists of an inner tube 16, and an ampoule 17 that encloses the fixing jig 15 and the inner tube 16,
This is an apparatus for growing an epitaxial layer on a substrate by rotating the ampoule 17 and bringing the molten epitaxial growth melt 20 onto the substrate 11 into contact with the ampoule 17.
A melt reservoir 18 is provided between the inner wall of the tube 7 and the outer wall of the inner tube 16, and the fixing jig 15 is provided with a melt outflow pipe 19 that reaches the melt reservoir 18 from the end of the groove 13 of the fixing jig. During epitaxial growth in which the substrate 11 and the melt 13 are brought into contact, excess melt is removed from the melt outflow pipe 19.
The structure is such that it is guided closer to the melt reservoir 18.

[For production]

The apparatus of the present invention rotates the ampoule to bring the epitaxial growth melt into contact with the epitaxial growth substrate,
When growing an epitaxial layer on the substrate, the excess melt on the substrate flows out from the melt outflow pipe into the melt reservoir, so that the dimension in the depth direction of the melt for epitaxial layer growth on the substrate is adjusted relative to the epitaxial growth. This is to prevent the epitaxial layer from growing abnormally at the periphery of the substrate.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view of the liquid phase epitaxial growth apparatus of the present invention before the ampoule is rotated, FIG. 2 is a cross-sectional view taken along line II' in FIG. 1, and FIG. FIG. 4 is a cross-sectional view taken along the line mm--m' of FIG. 1.

As shown in FIGS. 1 to 4, the liquid phase epitaxial growth apparatus of the present invention has grooves 1 that sandwich support plates 12 that support an epitaxial growth substrate 11 made of CdTe'.
Groove 13 of fixing jig 15 made of cylindrical quartz provided with 3
A melt outflow pipe 19 is provided between the outer wall of the inner pipe 16 and the inner wall of the ampoule 17 from the end thereof to a melt reservoir 18 formed by crushing the outer wall of the inner pipe 16.

Although only two melt outflow pipes 19 are shown in this embodiment, a plurality of melt outflow pipes 19 may be provided in the direction perpendicular to the paper surface.

After installing the epitaxial growth substrate 11 described above on the support plate 12 of the apparatus of the present invention, the support plate 12 is held between the grooves 13 of the fixing jig 15, and the fixing jig and mercury,
An ampoule 1 contains a melt forming material 20 for epitaxial growth formed by mixing and melting a predetermined amount of cadmium and tellurium.
After the ampoule 17 is inserted into the ampoule 7 and the inside of the ampoule 17 is evacuated, one end C of the ampoule 17 is melted and sealed.

Next, this ampoule 17 is inserted into a furnace core tube (not shown) in a heating furnace, heated at a temperature of 500''C, and then the epitaxial growth material 20 described above is heated and melted at a temperature of 500°C.

Next, the ampoule 17 is rotated 180 degrees in the direction of arrow B,
A substrate 11 and a melt 20 for epitaxial growth are brought into contact with each other, and an epitaxial layer is formed on the substrate while lowering the temperature of the melt at a predetermined temperature gradient.

FIG. 5 shows a state in which the epitaxial growth apparatus of the present invention shown in FIG. The minimum amount of melt necessary for epitaxial growth will remain on the substrate, and the depth dimension l of the melt in contact with the substrate will become small (as a result, the epitaxial layer will become thinner at the periphery of the substrate). Abnormal growth is avoided.

〔Effect of the invention〕

As is clear from the above description, the liquid phase epitaxial growth apparatus of the present invention has the effect of obtaining a high quality epitaxial layer that does not cause abnormal growth in the peripheral area of the epitaxial growth substrate.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the device of the present invention, FIG. 2 is a sectional view taken along line I-I' in FIG. 1, and FIG. 3 is a sectional view taken along line nn' in FIG. 1. Figure 4 is the first
5 is a sectional view of the device of the present invention in operation; FIG. 6 is a sectional view of the conventional device; FIG. 7 is a sectional view taken along line Vl-Vl of FIG. 'Cross section along line 8th
The figure is a cross-sectional view of a conventional apparatus during epitaxial growth. In the figure, 11 is an epitaxial growth substrate, 12 is a support plate, and 13 is a substrate for epitaxial growth.
14 is a groove, 15 is a fixing jig, 16 is an inner tube, 17
is an ampoule, 18 is a melt reservoir, 19 is a melt outflow tube, hemisheath e embryonic shell 1 taibu diagram Figure 1 ke■ flash I-work'1; −IVL=3X −r= @1Ir
ZFigure 3Figure 4rA Figure 5

Claims (1)

[Scope of Claims] A substrate (11) having a groove (13) for sandwiching a support plate (12) that holds a substrate (11) for epitaxial growth;
A fixing jig (1) having a recess (14) for accommodating a melted epitaxial growth melt (20) at a position facing the
5) and the inner tube (1) for preventing positional fluctuation of the fixing jig (15).
6), and an ampoule (17) enclosing the fixing jig (15) and the inner tube (16), the ampoule (17)
An apparatus for growing an epitaxial layer on a substrate by rotating the substrate (11) and bringing the molten epitaxial growth melt (20) into contact with the substrate (11), the inner wall of the ampoule (17) and the outer wall of the inner tube (16) A melt reservoir (18) is provided between the fixing jig (
15) from the groove (13) of the fixing jig.
A melt outflow pipe (19) reaching the melt outflow pipe (19) is provided to guide excess melt from the melt outflow pipe (19) to the melt reservoir (18) during epitaxial growth in which the substrate and the melt (20) are brought into contact with each other. A liquid phase epitaxial growth device featuring: