JP3342548B2 - Method for producing member for liquid phase epitaxial growth - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a member used for performing liquid phase epitaxial growth of a compound semiconductor (using indium, gallium, arsenic, and phosphorus). The present invention relates to a method for producing a member for liquid phase epitaxial growth typified by a boat, a slider, and other jigs in which no separation is observed and there are no open pores.

[0002]

2. Description of the Related Art Liquid phase epitaxial growth is a kind of thin film growth technique in a semiconductor device manufacturing process, and refers to a method of growing a thin film directly on a semiconductor substrate using a supersaturated melt such as gallium.

In the slide boat method, the apparatus for liquid phase epitaxial growth comprises a boat for holding a supersaturated melt, a slider for moving a semiconductor substrate, other jigs, and the like. For other jigs, high-purity, high-density graphite has been used.

[0004]

However, the above graphite has the characteristics of high thermal conductivity, high purity, high thermal shock resistance, and low reactivity with metals, but the surface of the graphite has Due to the presence of open pores, impurities are adsorbed, phosphorus and arsenic enter, and they come into contact with the grown film during liquid phase epitaxial growth, and the characteristics of the epitaxial film deteriorate.

[0005] Further, graphite has a drawback such that graphite powder is easily detached from the surface. However, this graphite powder also causes deterioration of the characteristics of the epitaxial film.

For this reason, pitch obtained by incompletely pyrolyzing an organic polymer (vinyl chloride) in a graphite material family is mixed with an aromatic solvent to form a slurry,
An attempt has also been made to apply the slurry to an appropriate molded product and then bake it (see Japanese Patent Publication No. 52-39684) to coat the molded product with glassy carbon to prevent the generation of graphite powder. However, in this method,
A sufficient effect could not be obtained because a thick coating could not be formed or cracks occurred.

The present invention solves the above-mentioned problems in the prior art and manufactures members for liquid phase epitaxial growth typified by boats, sliders and other jigs in which graphite powder is not detached and has no open pores. It is intended to provide a method .

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for manufacturing a member for liquid phase epitaxial growth .
The construction method is composed of graphite boats, sliders and their
Cover other jigs with polycarbodiimide resin, and then
The polycarbodiimide resin in an inert atmosphere with carbon
And carbonized polycarbodiimide resin
It is characterized in that a part is made to enter the inside of the member .

That is, the present inventors have focused on a polycarbodiimide resin, which is a resin having a high carbon content after firing and carbonization and a high yield, and carbonized this resin to coat a member for epitaxial growth. For example, the inventor of the present invention obtained the idea that a member for epitaxial growth in which graphite powder was not detached and free of open pores could be obtained. As a result of further research, the present invention was completed.

Hereinafter, the present invention will be described in detail.

The liquid phase epitaxial growth member to be used in the present invention is used in the slide boat method. As described above, the member for moving the supersaturated melt and the semiconductor substrate are moved. And other jigs, and these members are usually manufactured by processing graphite.

In the present invention, the above-mentioned member for liquid phase epitaxial growth is coated with a carbonized polycarbodiimide resin.

The above-mentioned polycarbodiimide resin itself is known or can be produced in the same manner as known ones. US Pat. No. 2,941,95
No. 6, JP-B-47-33279; Or
g. Chem. , 28 , 2069-2075 (196
3) Chemical Review 198l, vo
l. 8l. No. For example, it can be easily produced by a condensation reaction involving the removal of carbon dioxide from an organic diisocyanate in the presence of a carbodiimidization catalyst.

The organic diisocyanate used in the production of the above polycarbodiimide resin may be any of aliphatic, alicyclic, aromatic and aromatic-aliphatic types. Used alone or
Two or more kinds may be used in combination as a copolymer.

The polycarbodiimide resin used in the present invention has the following formula: -RN = C = N- (wherein R represents an organic diisocyanate residue)
And a homopolymer or a copolymer comprising at least one type of repeating unit represented by the formula:

As R in the above formula which is an organic diisocyanate residue, an aromatic diisocyanate residue is particularly preferable (here, the organic diisocyanate residue is a group obtained by removing two isocyanate groups (NCO) from an organic diisocyanate molecule). The rest). Specific examples of such a polycarbodiimide resin include the following.

Embedded image

In the above formulas, n is 10 to 10 and 0.
00, preferably in the range of 50 to 5,000, and the terminal of the polycarbodiimide resin may be sealed with monoisocyanate or the like.

The above-mentioned polycarbodiimide resin can be obtained as a solution or as a powder precipitated from the solution. The polycarbodiimide resin thus obtained is, in the case of a polycarbodiimide resin obtained in a liquid form,
The polycarbodiimide resin obtained as a powder can be used as it is as a coating solution, or it can be used as a coating solution after dissolving in a solvent to form a liquid.

In the present invention, a coating is first formed on the surface of a liquid phase epitaxial growth member typified by a boat, a slider, and other jigs using a coating solution containing the above polycarbodiimide resin. The method for forming the coating may be any method such as vacuum impregnation, ultrasonic impregnation, brushing, spraying, etc., and is not particularly limited. When forming this coating, a part of the coating solution containing the polycarbodiimide resin enters the open pores of graphite.

The above-mentioned member for epitaxial growth having a film formed on the surface is thereafter dried at a temperature of, for example, 60 ° C. to 300 ° C.

Next, the member for epitaxial growth, on which the polycarbodiimide resin film is formed on the surface as described above, is heated to carbonize the polycarbodiimide resin, thereby obtaining the desired member for liquid phase epitaxial growth. it can. This carbonization step is performed in an inert atmosphere such as in a vacuum or nitrogen gas, and the final firing temperature at that time is 500 ° C to 3000 ° C.

Since the thus obtained epitaxial growth member is covered with the carbonized polycarbodiimide resin, the open pores of graphite are completely filled, and the graphite is dense and free from cracks. In addition, the graphite powder does not desorb at all, and furthermore, phosphorus, arsenic and other impurities which have entered and adsorbed into the graphite do not appear on the surface.

Now, the present invention will be described in further detail with reference to Examples.

[0024]

【Example】

Example A polycarbodiimide solution was obtained as follows. A mixture of 2,4-tolylene diisocyanate / 2,6-tolylene diisocyanate (80:20) (TDI) (54 g) in 500 ml of tetrachloroethylene was used to prepare a carbodiimidation catalyst (1-phenyl-3-methylphospholene oxide). The mixture was reacted at 120 ° C. for 4 hours together with 12 g to obtain a polycarbodiimide resin solution.

Separately, a boat member, a slider material and a boat lid of the liquid phase epitaxial growth apparatus shown in FIG. 1 are made of Toyo Carbon isotropic graphite (CIP product, density 1.8).
5 g / cm ³ ). That is, the boat member 1
Has a total length of 75 mm and a width of 30 mm, and a round hole 2, 3 is formed in the boat member 1, and a gap 5 for inserting a slider 4 is provided near the bottom surface of the boat member 1 so that the round holes 2, 3 Has no bottom, and the slider 4 prevents the solution from flowing out of the round holes 2 and 3 from flowing out. The width of the slider 4 is 15 mm, the surface is provided with a recess 6 having a length of 200 mm and a thickness of 3 mm for mounting a single crystal, and the boat lid 7 has a height of 15 m.
mφ plate shape.

These graphite members are impregnated with the above-mentioned polycarbodiimide resin solution, coated, and dried in order to dry the solution.
Heat treatment was performed at 0 ° C. for 10 minutes, at 120 ° C. for 10 minutes, and at 200 ° C. for 10 minutes. Thereafter, the polycarbodiimide resin was carbonized at 1500 ° C. in vacuum to prepare an example of the member for epitaxial growth of the present invention.

Next, metal gallium is put into the round holes 2 and 3 of the boat body 1 and the lid 7 is closed.
, A gallium-arsenic substrate and a gallium-arsenic substrate for epitaxial growth were placed. The slider 4 was adjusted so that the lower portions of the round holes 2 and 3 did not come into contact with any of the substrates, and the slider 4 was placed in a quartz tube and evacuated. Next, hydrogen gas was flowed into the electric furnace to raise the temperature. When the gallium melted, the slider 4 was moved to saturate gallium-arsenic in the gallium by the gallium-arsenic substrate, and then cooling was started. Next, the gallium-arsenic substrate for epitaxial growth was moved under the round hole, cooling was continued, and gallium-arsenic was grown. Epitaxial growth was performed three times under the same method and under the same conditions. The conductivity type, carrier concentration, mobility, carbon content and oxygen content of the gallium-arsenic obtained by this method were measured. Table 1 shows the results.

Comparative Example A graphite member was formed in the same shape and dimensions as in the example, and was not subjected to polycarbodiimide coating, and epitaxial growth was performed three times under the same conditions as in the example. The conductivity type, carrier concentration, mobility, carbon content and oxygen content of the gallium-arsenic obtained by this method were measured. The results are shown in Table 1 (the conductivity type of the comparative example is all p-type due to the influence of impurities in graphite).

[Table 1]

[0029]

As shown in Table 1 above, according to the present invention ,
Since the manufactured member for epitaxial growth is covered with a carbonized polycarbodiimide resin, graphite powder is detached from the surface or phosphorus, arsenic and other impurities that have entered graphite and are adsorbed come out to the surface. Therefore, a good semiconductor having a low carrier concentration, a high mobility, and a small amount of impurities can be manufactured.

[Brief description of the drawings]

FIG. 1 is a partially sectional side view showing an example of a member for epitaxial growth of the present invention.

[Explanation of symbols]

 Reference Signs List 1 boat member 2, 3 round hole 4 slider 6 gallium-arsenic substrate holder 7 boat lid

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-62-270489 (JP, A) JP-A-3-247504 (JP, A) JP-A-4-36369 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01L 21/208

Claims (2)

(57) [Claims] 1. A graphite boat, a slider, and other jigs are coated with a polycarbodiimide resin, and then the polycarbodiimide resin is carbonized in an inert atmosphere, and a part of the carbonized polycarbodiimide resin. Of a member for liquid phase epitaxial growth, characterized by infiltrating the inside of the member. Wherein carbonization in an inert atmosphere, 500 ° C.
The method for producing a member for liquid phase epitaxial growth according to claim 1, wherein the method is performed in a temperature range of ０００3000 ° C.