JPH0625955Y2 - Liquid phase epitaxial growth system - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of a liquid phase epitaxial growth apparatus. Compound semiconductor crystals containing lead (Pb), such as lead-tin-tellurium
(Pb _1-x Sn _x Te) or a compound semiconductor crystal containing mercury (Hg), for example, mercury-cadmium-tellurium (Hg _1-x Cd _x Te) or the like has a narrow energy gap infrared detection element, infrared laser element, It is well known that it is used as a material for forming a photoelectric conversion element such as.

As a method for easily forming such a compound semiconductor crystal such as Hg _1-x Cd _x Te with a simple apparatus, a gradient type liquid phase epitaxial growth method has been conventionally used.

[0003]

2. Description of the Related Art A conventional apparatus used in such a gradient type liquid phase epitaxial growth method will be described with reference to FIG.

As shown in the drawing, a reaction tube 2 made of quartz is installed inside an annular heating furnace 1 which moves up and down with a point A as a fulcrum like a seesaw, and inside the reaction tube. Has a quartz ampoule 3 installed. And, in the ampoule 3, cadmium tellurium for epitaxial growth
(CdTe) substrate 4 and Hg _1-x Cd _x Te crystal layer material 5 to be formed on the substrate 5 mercury (Hg), cadmium (Cd), tellurium (Te)
Is weighed so as to have a predetermined composition and filled with an alloyed material, and after exhausting the ampoule, one end of the ampoule is sealed.

The substrate 4 is placed on one end of the ampoule 3 by inclining it using a suitable quartz jig (not shown), and the Hg _1-x Cd _x Te crystal layer forming material 5 is The other end of the ampoule 3 is filled so as to face the substrate 4.

In such a state, the temperature of the heating furnace 1 is raised to melt the forming material 5 to form a melt, and then the heating furnace 1 is tilted in the direction of arrow B to transfer the melt 5 to the substrate 4. The substrate 5 is immersed in the melt 5 and then the temperature of the heating furnace is lowered with a predetermined temperature gradient to form Hg _1-x Cd _x on the substrate 4.
It forms a Te crystal layer.

When a crystal layer having a predetermined thickness is formed, the tilted heating furnace 1 is moved in the opposite arrow C direction to return to the original tilted state, whereby the melt is melted from the substrate 4. Except for this, the growth of the crystal layer is stopped.

[0008]

However, such a conventional apparatus requires a moving mechanism for moving the heating furnace up and down with a predetermined size to largely move the entire reaction tube, and the apparatus is complicated. It causes the drawback that

Further, such an apparatus has many drawbacks such as a large amount of melt required for epitaxial growth in the ampoule. In order to eliminate the above-mentioned drawbacks, the present invention makes it possible to easily grow an epitaxial crystal layer without moving the heating furnace up and down like a seesaw during epitaxial growth and by using a small amount of the melt of the crystal layer forming material. The purpose is to provide a growth apparatus.

[0010]

A liquid phase epitaxial growth apparatus for achieving the above object is a heat-resistant sealed tube and a position deviated to the upper side from the center of the surface inscribed in the sealed tube and facing each other. And a pair of supporting members each having a recess for supporting the substrate, and a space defined between the supporting members in a state in which a substrate to be crystal-grown between the recesses is held through the side of the substrate. The sealed tube is formed by arranging the substrate so as to be divided into two spaces that communicate with each other in the upper and lower directions, and arranging a melt of the crystal layer forming material in a lower space facing one surface of the substrate. When it is rotated, the melt moves to the other space and contacts the other surface of the substrate.

[0011]

In the liquid phase epitaxial growth apparatus of the present invention, since the epitaxial growth surface of the substrate is on the backside of the material for forming the epitaxial layer, which is a melt, the sealed tube is heated to form the material for forming the epitaxial layer. At this time, even if the epitaxial layer forming material bumps, the bumped substance does not adhere to the epitaxial layer forming surface of the substrate, and a high quality epitaxial crystal can be obtained. Also, when the substrate is placed on a heat-resistant quartz plate that supports the substrate as in another embodiment of the present invention, no epitaxial crystal grows on the back side of the substrate, and when the sealed tube is rotated, the substrate is not used alone. The pressure is also relieved by the heat-resistant quartz plate supporting the substrate. In addition, since the oxide (sludge) of the melted epitaxial growth material at the side edge of the melted epitaxial growth material that supports the substrate when rotating the sealed tube is scooped out and removed, the epitaxial growth substrate A high quality epitaxial crystal can be obtained because the surface of is deposited on the epitaxial growth material. Further, even when the solid epitaxial growth material and the substrate are introduced and sealed in the quartz tube, the surface of the substrate for epitaxial growth is formed on the surface opposite to the solid epitaxial growth material. A high-quality epitaxial crystal can be obtained without causing scratches on the surface of the substrate.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of the liquid phase epitaxial growth apparatus of the present invention, and FIG. 2 is a sectional view of the above perspective view.

As shown in FIGS. 1 and 2, the liquid phase epitaxial growth apparatus of the present invention comprises a heat-resistant sealed tube 14 made of quartz and a cylindrical carbon housed in the heat-resistant sealed tube 14 so as to be inscribed therein. Consisting of a pair of substrate support members 11a, 11b,
Recesses for substrate engagement, that is, recessed grooves 13a and 13b are provided at positions deviated from the centers of the surfaces of the substrate support members 11a and 11b facing each other.

The case of forming an Hg _1-x Cd _x Te epitaxial layer on the CdTe substrate 12 using such a liquid phase epitaxial growth apparatus will be described.
The pair of substrate support members 11a, 11b in a state of sandwiching and holding 12 between the opposing grooves 13a and 13b, the other end is inserted into a heat-resistant encapsulating tube 14 having the other end sealed, and the substrate 12 is placed in the upper part of the tube. An alloy 15 of the material Hg, Cd, Te of the crystal layer to be formed on the substrate 12 is filled in the lower portion facing the CdTe substrate 12 while being arranged.
The amount of the material is set so that the whole substrate can be used when the sealed tube is rotated in a later step. After that, the inside of the heat-resistant sealed tube 14 made of quartz is evacuated and then welded and sealed at the end D.

After inserting the liquid phase epitaxial growth apparatus in such a state into a reaction tube (not shown), the reaction tube is heated in a heating furnace (not shown) to melt the material of Hg _1-x Cd _x Te. To do. After that, the heat-resistant sealed tube 14 made of quartz is rotated about 180 ° to bring the mirror-polished surface E of the substrate 12 into contact with the melt of Hg _1-x Cd _x Te, and then the temperature of the heating furnace is lowered to lower the temperature of the substrate 12. Hg on
Form an epitaxial layer of _1-x Cd _x Te. Then substrate 12
When the epitaxial layer having a predetermined thickness is formed on the substrate 12, the sealed tube 14 is rotated again by about 180 ° to remove Hg _1-x Cd _x Te from the substrate 12.
Then, the melt is removed to form an epitaxial layer of Hg _1-x Cd _x Te on the substrate 12 with a predetermined thickness.

As another embodiment, a space such that a heat-resistant member such as quartz having a size longer than that of the CdTe substrate 12 is previously held in the groove 13 of FIG. 2 and the substrate 12 is sandwiched between the heat-resistant members. Providing a protrusion having, and installing a CdTe substrate in this space, the substrate 12 will not be twisted or damaged when the sealed tube is rotated, and the back surface of the substrate 12 will not be damaged.
The formation of the Hg _1-x Cd _x Te crystal layer can be avoided.

Further, since the substrate supporting members 11a and 11b are divided, the substrate 12 can be mounted easily and the growth apparatus can be formed at a low cost. Further, the apparatus of the present invention can be applied to the case where a compound semiconductor crystal containing lead is formed on the compound semiconductor substrate containing lead, in addition to the above embodiments.

[0018]

As described above, according to the liquid phase epitaxial growth apparatus of the present invention, it is possible to epitaxially grow a compound semiconductor crystal containing an easily evaporative material such as Hg by a simple apparatus using a heat resistant sealed tube. Yes, and because the material of the crystal layer to be formed on the substrate only needs to be installed in the region surrounded by the heat-resistant substrate support member, a small amount compared to conventional devices can be used. The cost of growing epitaxial crystals is reduced. Even when the solid epitaxial growth material that is the material for the epitaxial growth, the epitaxial growth substrate, and the quartz tube are enclosed in the ampoule, the epitaxial growth surface of the epitaxial growth substrate does not face each other. There is an effect that scratches are eliminated and a high quality epitaxial crystal is obtained.

Further, in the apparatus of the present invention, even if the melt of the crystal layer forming material before the epitaxial growth is heated and melted and bumps and adheres to the substrate, it adheres to the surface opposite to the growth surface. There is no effect on the crystal growth surface.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of a liquid phase epitaxial growth apparatus of the present invention.

FIG. 2 is a sectional view of an embodiment of the liquid phase epitaxial growth apparatus of the present invention.

FIG. 3 is a schematic diagram of a conventional liquid phase epitaxial growth apparatus.

[Explanation of symbols]

1 ring furnace 2 reaction tube 3 ampoule 4,12 CdTe substrate 5,15 Hg _1-x Cd _x Te material 11a, 11b substrate support members 13a, 13b groove 14 heat-resistant sealed tube A fulcrum B, C rotation direction of heating furnace Indicated arrow D Edge E Polished surface of substrate (surface for epitaxial growth)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Mitsuo Yoshikawa 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Within Fujitsu Limited (56) References Japanese Patent Publication No. 51-10472 (JP, B1) (JP, B2)

Claims (2)

[Scope of utility model registration request] 1. A heat-resistant sealed tube (14), and a recess (13a, 13b) for supporting a substrate at a position deviated upward from the center of the surfaces inscribed in the sealed tube (14) and facing each other. ) With a pair of support members (11a, 11b), the support member (11a, 11b) in a state of holding the substrate (12) to be crystal grown between the recesses (13a, 13b) The substrate (12) is installed so that the space defined therebetween is divided into two spaces that vertically communicate with each other through the side of the substrate (12) and faces one surface of the substrate (12). When the sealed tube (14) is rotated with the melt (15) of the crystal layer forming material arranged in the lower space, the melt (15) moves to the other space and the substrate
A liquid phase epitaxial growth apparatus characterized in that it is configured to come into contact with the other surface of (12). 2. The substrate (12) is held on a heat-resistant member having a size larger than the size of the substrate (12), and the recesses (13a, 13a, 11a, 11b) facing each other of the pair of support members (11a, 11b) are opposed to each other. The liquid phase epitaxial growth apparatus according to claim 1, wherein the apparatus is sandwiched between 13b).