JP2883405B2 - Crucible for pulling single crystal and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a crucible for pulling a single crystal and a method for producing the same, and in particular, a compound semiconductor single crystal made of a highly anisotropic pyrolytic boron nitride material having a developed layer structure. The present invention relates to a lifting crucible and a method for manufacturing the same.

(Prior Art) Regarding a method for producing pyrolytic boron nitride (hereinafter abbreviated as P-BN), a thermal chemical vapor deposition of a boron halide and ammonia is performed at a temperature of 1,450 to 2,300 ° C. and a pressure of 50 mmHg or less. Is known (see US Pat. No. 3,152,006), and the P-B obtained by this method is known.
Since the N crystal is oriented in the deposition direction, the N crystal has an anisotropic structure having a layered structure and a crystal orientation degree of 10 to 100.

For these methods, an alkyl borate ester and ammonia are thermally decomposed and deposited at a temperature of 1,100 to 1,900 ° C. and a pressure of about 1 Torr (see U.S. Pat. No. 3,692,566). Although a method of performing the treatment with torr (see U.S. Pat. No. 4,096,297) is also known, the P-BN obtained in this case is not a layered structure but isotropic and has a degree of crystal orientation of 1%.
It will be as low as ~ 10.

Further, as a method for producing this P-BN, it is also known to react a boron halide and ammonia at a temperature of 1,100 to 1,600 ° C. in the presence of a small amount of an alkyl borate (US Pat. No. 4,544,535). According to this, it does not form a layered structure, but has anisotropy and a crystal orientation degree of 10 to 100 can be obtained.

(Problems to be Solved by the Invention) However, when P-BN obtained by these known methods is used as a crucible for pulling up a compound semiconductor crystal,
Due to the good wettability between the P-BN and the compound semiconductor melt, heat-shrinkage stress is generated in the crucible during cooling, and the inner surface of the crucible made of P-BN having a layered structure peels off according to the layer. However, there is a disadvantage that it can be used only about 20 times due to a large amount of peeling, and a crucible made of P-BN having no layered structure is broken and cannot be used repeatedly. is there.

(Means for Solving the Problems) The present invention relates to a crucible for pulling up a compound semiconductor single crystal which solves such disadvantages and a method for producing the same, which comprises P-BN and halogen having a crystal orientation degree of 1,000 or more. The present invention relates to a method for producing P-BN, comprising reacting boron halide, an alkyl borate ester and ammonia at a temperature of 1600 ° C. or more and 50 Torr or less.

That is, the present inventors have conducted various studies on a method for producing P-BN which is suitable as a crucible material for pulling a compound semiconductor single crystal, and found that the reaction with boron halide, alkyl borate and ammonia was performed at 1600 ° C. or more, Five
When the reaction is carried out at 0 torr or less, a P-BN having a more developed layer structure and a degree of crystal orientation of 1,000 or more than conventionally known P-BN is obtained.
-BN is obtained, and this material has extremely high anisotropy.If this is used as a crucible material for pulling up a compound semiconductor single crystal, the delamination that occurs during cooling due to the developed layer structure has a depth It has been found that it is possible to increase the number of repetitive uses, since the spread in the direction is prevented and the amount of peeling is extremely small.
The present invention was completed by conducting research on this reaction condition.

 This will be described in more detail below.

(Function) The present invention produces a compound semiconductor single crystal pulling crucible using P-BN having a degree of crystal orientation of 1,000 or more and P-BN obtained by the reaction of boron halide, alkyl borate ester and ammonia. It is in.

The production of P-BN according to the invention is carried out by reaction with boron halides, alkyl borate esters and ammonia.

The boron halide used here is boron trichloride,
It may be something like boron trifluoride, and the alkyl borate used here is methyl borate,
Ethyl borate and the like may be used, and the ammonia used here may be used by a conventionally known method. However, these require that the target compound semiconductor single crystal pulling crucible has high purity. Therefore, it is necessary that all of them are sufficiently purified and of high purity.

If the compounding ratio of boron halide, alkyl borate and ammonia is less than 0.1 mol per mol of boron halide, the layer structure will not be developed because the amount is less than 0.1 mol, and if it is more than 1.0 mol, no layer will be formed. Thus, the amount of ammonia may be in the range of 0.1 to 1.0 mol. If the amount of ammonia is less than 2 mol per mol of boron halide, the amount is too small and excess boron is increased in the product. Then, the amount of unreacted ammonia increases, so it may be in the range of 2 to 10 mol.

In addition, since this reaction obtains P-BN as a high-purity one, it is usually preferable to carry out this reaction in a reaction vessel made of high-purity graphite.
P-BN obtained by performing at a temperature of 100 to 1,600 ° C
Does not have a layered structure,
It is necessary to carry out the above at, for example, 1,700 to 1,900 ° C., but in this case, if the pressure is 50 Torr or more, a film is not formed. When the reaction is performed at a temperature as high as 1600 ° C. or more and at a temperature of 50 Torr or less, the obtained P-BN has a more developed layer structure than that obtained by a conventionally known method, and has an extremely anisotropy. High and the expression Here, I (002) is the X-ray diffraction intensity of the (002) plane parallel to the deposition surface, I (100) is the X-ray diffraction intensity of the (100) parallel to the deposition surface, and I002 (002) is the The vertical is the X-ray diffraction intensity of the (002) plane, and I⊥ (100) is the X-ray diffraction of the (100) plane perpendicular to the deposition plane.
The degree of crystal orientation indicated by X-ray diffraction intensity is 1,000 to 100,00, which is significantly higher than that of the conventional product of 1 to 100.When this is used as a crucible for pulling a compound semiconductor single crystal, this developed layer structure is The advantage of preventing the spreading in the depth direction is that the separation can be made significantly thinner than the conventional product.

(Examples) Examples of the present invention and comparative examples will be described below.

Example 1 1 mol of boron trichloride per hour, 0.2 mol of methyl borate and 10 mol of ammonia were fed into a high-purity graphite reaction vessel having an inner diameter of 150 mmφ and subjected to thermal chemical vapor deposition at 1600 ° C. and 5 Torr. Since a P-BN having a layered structure and a degree of crystal orientation of 33,000 was obtained, a crucible having a diameter of 4 inches was formed therefrom.

Then, using this crucible, the melting and cooling of boric anhydride, which is used as a sealant when pulling up a compound semiconductor single crystal, is performed.
When the amount of peeling of the crucible at that time was measured 39 times repeatedly, it was 0.3 g / time.

Example 2 1 mol of boron trichloride, 0.3 mol of methyl borate and 5 mol of ammonia were supplied to a high-purity graphite reaction vessel having a diameter of 150 mmφ per hour, and P-BN was deposited by thermal chemical vapor deposition at 1,700 ° C. and 5 Torr. As prepared, this P-BN had a layered structure and a crystal orientation degree of 18,000.

Then, a crucible having a diameter of 4 inches was made from this P-BN, and the same test as in Example 1 was performed on the crucible. The amount of peeling of the crucible was 0.4 g / time on average.

Example 3 1 mol of boron trichloride, 0.8 mol of methyl borate and 3 mol of ammonia per hour were supplied to a high-purity graphite reactor having a diameter of 150 mmφ and subjected to thermal chemical vapor deposition at 1,800 ° C. and 7 Torr to form P-BN. When made, this P-BN had a layered structure and a crystal orientation of 1,900.

Then, a crucible having a diameter of 4 inches was made from this P-BN, and the same test as in Example 1 was performed. The amount of peeling of the crucible was 0.3 g / time on average.

Example 4 1 mol of boron trichloride, 0.5 mol of methyl borate and 3 mol of ammonia were fed to a high-purity graphite reactor having a diameter of 150 mmφ per hour, and subjected to thermal chemical vapor deposition at 1,900 ° C. and 10 Torr to form P-BN. When produced, this P-BN had a layered structure and had a crystal orientation of 1,100. Then, a crucible having a diameter of 4 inches was made from this P-BN, and the same test as in Example 1 was performed. The amount of peeling of the crucible was 0.3 g / time on average.

Example 5 1 mol of boron trifluoride, 0.2 mol of methyl borate and 5 mol of ammonia were supplied to a high-purity graphite reaction vessel having a diameter of 150 mmφ per hour, and were subjected to thermal chemical vapor deposition at 1,800 ° C. and 3 Torr to form P-BN. As a result, this P-BN had a layered structure and a degree of crystal orientation of 3,000.

Then, a crucible having a diameter of 4 inches was made from this P-BN, and the same test as in Example 1 was performed on the crucible. The amount of peeling of the crucible was 0.4 g / time on average.

Example 6 1 mol of boron trichloride, 0.6 mol of methyl borate and 5 mol of ammonia were fed to a high-purity graphite reaction vessel having a diameter of 180 mmφ per hour, and P-BN was deposited by thermal chemical vapor deposition at 1,800 ° C. and 10 Torr. When made, this P-BN had a layered structure and had a degree of crystal orientation of 5,000.

Then, a crucible having a diameter of 4 inches was made from this P-BN, and the same test as in Example 1 was performed. The amount of peeling of the crucible was 0.3 g / time on average.

Comparative Example 1 mole of boron trichloride and 3 moles of ammonia per hour
0mmφ high-purity graphite reaction vessel
When P-BN was produced by thermal chemical vapor deposition under the conditions of 5 ° C. and 5 Torr, this P-BN had a layered structure, but the crystal orientation degree was as low as 28.

Then, a crucible having a diameter of 4 inches was prepared from this P-BN, and the same test as in Example 1 was performed on the crucible. The amount of peeling of the crucible was 0.2 g / time on average.

(Effect of the Invention) The present invention is to manufacture a crucible for pulling up a compound semiconductor single crystal using P-BN having a layer structure developed and having high anisotropy. Alkyl ester and ammonia over 1,600 ° C, 5
It is characterized by reacting at 0 torr or less.According to this, a highly anisotropic material having a more developed layer structure than P-BN obtained by the conventional method is obtained. Has a degree of crystal orientation of 1,000 or more, and when this is used as a crucible for pulling up a compound semiconductor single crystal, this developed layer structure and degree of crystal orientation prevent spreading in the depth direction of peeling. Thus, this peel is significantly smaller than the peel in crucibles made from P-BN obtained in the prior art, thus giving the crucible the advantage that it can be used for a long time.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kenji Ito 2-13-1 Isobe, Annaka-shi, Gunma Prefecture Shin-Etsu Chemical Co., Ltd. Precision Functional Materials Laboratory (56) Reference US Patent 3152006 (US, A) ( 58) Field surveyed (Int. Cl. ⁶ , DB name) C30B 1/00-35/00

Claims (2)

(57) [Claims] 1. A crucible for pulling a single crystal, comprising a pyrolytic boron nitride material having a degree of crystal orientation of 1,000 or more. 2. A method for producing a single crystal pulling crucible, comprising using pyrolytic boron nitride obtained by reacting a boron halide, an alkyl borate ester and ammonia at a temperature of 1600 ° C. or more and 50 Torr or less.