JPH06263778A - Purification of organophosphorus compound - Google Patents

Abstract

PURPOSE:To provide an industrially advantageous method for purifying organophosphorus compounds serving as an material for epitaxial, growth, capable of safely purifying the compounds to a level of high purity generally required as a raw material for compound semiconductors and also capable of effectively removing water and other oxocompounds as impurities. CONSTITUTION:An organophosphorus compound of the formula RaH3-aP (R is 1-4C alkyl; (a) is an integer of 1-3) is brought into contact with an alkaline hydride. This hydride, which is used for removing the impurities contained in this compound, may be an alkali metal hydride or alkaline earth metal hydride (e.g. lithium hydride, sodium hydride, potassium hydride, rubidium hydride, cesium hydride, aluminum lithium hydride, calcium hydride, strontium hydride, barium hydride). To purify an organophosphorus compound using a metal hydride, this metal hydride is added to the organophosphorus compound followed by agitation at normal temperatures or under heating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying an organophosphorus compound useful as a material for epitaxial growth for producing a compound semiconductor.

[0002]

2. Description of the Related Art In recent years, compound semiconductors have been widely used in light emitting diodes, semiconductor lasers, high speed operation transistors (HEMTs) and the like. In manufacturing compound semiconductors, MOCVD
Recently, a method of epitaxially growing a crystal by ic chemical vapor deposition) has been actively performed. Compound semiconductors manufactured by such a method include, for example, III-
There are group V compound semiconductors and the like. Phosphine containing phosphorus is used as the raw material on the V group side.

The method using phosphine has a problem of safety. Phosphine is toxic. Moreover, since it is a gas at room temperature, it must be used at high pressure in the production of compound semiconductors. Use of toxic gas at high pressure is dangerous. In order to avoid such dangers of phosphine, the use of monoalkylphosphine has recently been proposed. Epitaxially grown films dislike carbon inclusion. Monoalkylphosphine is attracting attention as an alternative material because it is less toxic than phosphine because carbon is less likely to enter the epitaxial growth film.

A method for synthesizing a monoalkylphosphine includes
Z. anorg. Allg. Chem. 443, 42 (1978). And the like, there is a method for reducing phosphonyl chloride or phosphonous acid. Or J. Org. Chem. 24, 356 (195
There is also a method by a reaction between a phosphine and an olefin as described in 9). Of these, the method of reacting phosphine and olefin is the easiest to mass-produce.

To synthesize a monoalkylphosphine by reacting a phosphine with an olefin, a sulfonic acid compound is used as a catalyst. Therefore, the crude monoalkylphosphine obtained by synthesis usually contains a trace amount of sulfur compound even after purification. Therefore, the crude product is washed with an aqueous system. As a result, oxygen-containing compounds such as alcohol remain as impurities in the purified product in addition to water contained in the water system. If water and other oxygen-containing compounds remain, even a trace amount thereof causes an unexpected trouble in the electro-optical characteristics of the semiconductor crystal. Therefore, when making a semiconductor,
Organometallic compounds are generally purified by high precision distillation. However, until now, the high-purity monoalkylphosphine required for the production of compound semiconductors has not been sufficiently obtained only by the precise distillation purification method. As confirmed by the present inventor, such impurities could not be sufficiently removed even by an adsorption method applying, for example, zeolite or molecular sieve.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an organic phosphorus compound as a material for epitaxial growth can be safely purified to a high purity generally required as a raw material of a compound semiconductor. It is an object of the present invention to provide an industrially advantageous purification method that can effectively remove water and other oxygen-containing compounds.

[0007]

The method for purifying an organophosphorus compound of the present invention, which has been made to achieve the above-mentioned object, comprises contacting an organophosphorus compound represented by the following general formula 1 with an alkali hydride to obtain impurities. To remove. R _a H _3-a P ··· (1) In the above formula, R is an alkyl group having 1 to 4 carbon atoms. a is an integer of 1 to 3.

This method is preferably applied to the removal of impurities contained in the monophosphorus phosphine in which a is 1 among the organic phosphorus compounds represented by the general formula 1. Examples of the monoalkylphosphine in that case include mono-1,1-dimethylethylphosphine, mono-1-methylpropylphosphine, and monoethylphosphine. All of these are used as materials for epitaxial growth in the production of compound semiconductors. Among them, mono-1,1-dimethylethylphosphine is most suitable. The above-mentioned organophosphorus compound often contains trace amounts of oxygen-containing compounds such as water and alcohol, which are a part of the water system used for removing the catalyst, as impurities.

The alkali hydride that is brought into contact with the organic phosphorus compound containing impurities may be an alkali metal hydride or an alkaline earth metal hydride. Specific examples of the alkali metal hydride include lithium hydride, sodium hydride, potassium hydride, rubidium hydride, cesium hydride and lithium aluminum hydride. Specific examples of the alkaline earth metal hydride include calcium hydride, strontium hydride and barium hydride.

In order to purify the organic phosphorus compound using the metal hydride, the metal hydride is added to the organic phosphorus compound and stirred at room temperature or under heating. The addition of the metal hydride to the organic phosphorus compound may be carried out directly or the solution of the organic phosphorus compound may be added and the metal hydride may be added thereto.
The amount of the metal hydride added is 1 to 10 parts by weight, preferably 3 to 5 parts by weight, per 100 parts by weight of the organic phosphorus compound.
The removal of excess metal hydride is carried out simultaneously with the removal of the organophosphorus compound by filtration or distillation.

According to such a method, for example, mono-1,1-
Trace impurities can be efficiently removed from dimethylethylphosphine and the like. In addition to monoalkylphosphine, it can also be efficiently removed from dimethylphosphine, diethylphosphine, trimethylphosphine, and triethylphosphine.

[0012]

According to the present invention, trace amounts of impurities consisting of water and oxygen-containing compounds which cannot be removed by precision distillation are added to the organic phosphorus compound used as a material for epitaxial growth.
It can be effectively and safely purified to a high purity generally required as a raw material of a compound semiconductor by a simple apparatus. It becomes possible to manufacture a compound semiconductor having higher quality reliability.

[0013]

EXAMPLES Examples of the present invention will be described below. Example 1 120 g of isobutene was placed in an autoclave reaction vessel having a volume of 1 liter and replaced with nitrogen gas or helium gas.
100 g of n-decane and 120 g of phosphine were charged.
To this, 140 g of methanesulfonic acid was added as a catalyst under pressure, and the mixture was stirred for 2 hours while maintaining the temperature inside the container at 60 ° C.
Isobutene was reacted with phosphine. During the reaction, the pressure inside the autoclave increased to about 30 kg / cm ² . When the temperature had dropped to 30 ° C. after the reaction was completed, unreacted phosphine was exhausted from the autoclave. When the reaction solution was analyzed by gas chromatography, it was found that mono-1,1-dimethylethylphosphine was synthesized. Reaction yield is 4 based on isobutene
It was 4.4%.

When the reaction solution was allowed to stand, it was separated into an organic layer and an inorganic layer. The organic layer was separated and collected, 1N aqueous sodium hydroxide solution was added thereto, and the mixture was washed with stirring. When left to stand, it was separated into an organic layer and an inorganic layer. The organic layer was taken out and stored, and the aqueous layer was subjected to ICP emission spectroscopic analysis. Sulfur was detected from the result of the spectroscopic analysis. A series of operations including addition of an aqueous sodium hydroxide solution to the organic layer, separation of the organic layer and the inorganic layer, and emission spectroscopic analysis were repeated until no sulfur content was detected by the emission spectroscopic analysis. Ultrapure water was further added to the organic layer from which no sulfur was detected in the inorganic layer, and the mixture was stirred to wash the organic layer. When left to stand, it was separated into an organic layer and an aqueous layer. When the organic layer was preserved and the aqueous layer was analyzed, sodium hydroxide was detected. A series of operations of adding ultrapure water, stirring and washing, and analyzing the aqueous layer were repeated until sodium hydroxide was not detected. 3.0 g of calcium hydride was added to the organic layer from which sodium hydroxide was not detected in the aqueous layer, and the mixture was stirred at room temperature for 1 hour. After stirring at room temperature, heat and reflux for an additional 1
Stir for hours. Then, by distillation, 65.0 g of mono-1,1-dimethylethylphosphine was obtained.

The ratio of impurities detected by the gas chromatography / mass spectrometer after washing with ultrapure water and before adding calcium hydride and the ratio of impurities detected by the same device after distillation are shown. Shown in 1.

[0016]

[Table 1]

An attempt was made to manufacture an epitaxial crystal semiconductor using the mono-1,1-dimethylethylphosphine thus purified. Excellent electrical and optical properties were observed.

Comparative Example 1 In the same manner as in Example 1, mono-1,1-dimethylethylphosphine was obtained in which neither sulfur nor sodium hydroxide was substantially detected by ICP emission spectroscopy. 69.5 g of the obtained mono-1,1-dimethylethylphosphine was contacted with 3.0 g of molecular sieve in the same manner as in Example 1. Table 2 shows the analysis results of impurities before and after contacting with the molecular sieve.

[0019]

[Table 2]

From Example 1 and Comparative Example 1, it was found that the alkaline hydride has an excellent effect in removing impurities.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiromi Osaki, Hiromi Osaki, 28, Nishi-Fukushima, Kubiki-mura, Nakakubiki-gun, Niigata Prefecture Shin-Etsu Chemical Co., Ltd. Synthetic Technology Laboratory (72) Inventor Tadashi Sugiya 9-15-1 Kameido Research & Development Division, Nippon Kagaku Kogyo Co., Ltd. (72) Inventor Tomio Yanai 9-15-1 Kameido, Koto-ku, Tokyo Nihon Kagaku Kogyo Co., Ltd.

Claims (5)

[Claims] 1. The following general formula 1 R _a H _3-a P (1) (wherein R is an alkyl group having 1 to 4 carbon atoms, and a is 1 to 1).
A method for purifying an organophosphorus compound, which comprises contacting an organophosphorus compound represented by the formula 3) with an alkali hydride to remove impurities. 2. The purification method according to claim 1, wherein the alkaline hydride is sodium hydride, lithium aluminum hydride or calcium hydride. 3. The method for purifying an organophosphorus compound according to claim 1, wherein the organophosphorus compound is a monoalkylphosphine. 4. The monoalkylphosphine is mono-1,1-
The method for purifying an organic phosphorus compound according to claim 3, which is dimethylethylphosphine. 5. The method for purifying an organophosphorus compound according to claim 1, wherein the impurities include both water and an oxygen-containing compound.