JPH05139743A - Method for purifying germanium hydride - Google Patents

Abstract

(57) [Summary] [Objective] Oxygen contained as an impurity in germanium hydride is removed to obtain highly purified gas. [Composition] Germanium hydride alone or a gas diluted with hydrogen, nitrogen, argon or the like is brought into contact with a silicide of nickel or copper.

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 germanium hydride, and more particularly to a method for purifying germanium hydride capable of removing oxygen contained in germanium hydride as an impurity to an extremely low concentration. Germanium hydride is an important raw material for manufacturing germanium semiconductors, etc., and the amount of its use is increasing year by year, and at the same time as the performance of semiconductors increases, extremely low content of impurities is required. ing.

[0002]

2. Description of the Related Art Germanium hydride used in the manufacture of semiconductors is generally commercially available in the form of pure germanium or in the form of being filled with a cylinder diluted with hydrogen gas or an inert gas. These germanium hydrides include
Oxygen and water are contained as impurities, of which water can be removed by a dehumidifying agent such as synthetic zeolite. The oxygen content in commercially available germanium hydride is usually 10 ppm or less, but recent germanium hydride containing cylinders and the like, which is relatively low at 0.1 to 0.5 ppm, is commercially available. There is almost no known technique for efficiently removing oxygen contained in germanium hydride.

[0003]

Recently, it has become possible to purify arsine, phosphine, and hydrogen selenide used in the manufacture of semiconductors to a high degree of purity. For example, oxygen contained as impurities is as low as 0.01 ppm or less. You can get the level one. Therefore, germanium hydride having an oxygen content of 0.01 ppm or less is strongly desired. Further, these gases may be contaminated by impurities such as air during the supply process to the semiconductor manufacturing apparatus such as connecting the cylinder or switching the pipes, and thus it is desirable to finally remove them immediately before the apparatus.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to efficiently remove oxygen contained in germanium hydride to an extremely low concentration. As a result, germanium hydride was converted into nickel or copper. Oxygen concentration of 0.1ppm or less, more preferably 0.01
The present invention has been completed by finding that it can be removed up to ppm or less. That is, the present invention is a method for purifying germanium hydride, which comprises contacting crude germanium hydride with a silicide of nickel or copper to remove oxygen contained in the crude germanium hydride. The present invention is
Contained in germanium hydride alone, germanium hydride diluted with hydrogen (hydrogen gas base) and inert gas (inert gas base) such as nitrogen and argon (hereinafter collectively referred to as crude germanium hydride) Applied for oxygen removal.

In the present invention, nickel silicide includes Ni ₃ Si, Ni ₂ Si, Ni ₃ Si ₂ and Ni ₂ Si.
Nickel silicide and nickel generally known as Nix Siy such as ₃ and silicon bonded in various other forms. Further, as the silicon silicide of copper, Cu ₄
Copper, which is generally known as CuxSiy such as Si, Cu ₅ Si, and Cu ₃ Si, and copper in which silicon is bonded in various other forms. There are various methods for obtaining a silicide of nickel or copper. Among them, as a simple method, a silicide can be easily obtained by bringing nickel or copper into contact with silane. In this case, the nickel may be metallic nickel or an oxide of nickel, and the copper may be metallic copper or an oxide of copper such that nickel or a copper compound which is easily reduced is the main component. Further, a small amount of chromium, iron, cobalt or the like may be used as a metal component other than nickel or copper.

[0006] These nickel or copper may be used alone or in the form of being supported on a catalyst carrier or the like, but for the purpose of enhancing the contact efficiency between the surface of nickel or copper and gas. Usually, it is used in the form of being supported on a catalyst carrier or the like. As a method of supporting nickel on a carrier, for example, a carrier powder such as diatomaceous earth, alumina, silica-alumina, aluminosilicate and calcium silicate is dispersed in an aqueous solution of nickel salt, and an alkali is further added to the carrier powder to form nickel on the carrier powder. The cake obtained by precipitating the components, then filtering, and optionally washing with water is dried at 120 to 150 ° C. and then calcined at 300 ° C. or higher, and the calcined product is crushed, or NiC
Inorganic salts such as O ₃ , Ni (OH) ₂ and Ni (NO ₃ ) ₂ and organic salts such as NiC ₂ O ₄ and Ni (CH ₃ COO) ₂ are calcined and crushed, and then heat resistant cement is added thereto. Examples include mixing and firing. These are usually formed into a molded product by extrusion molding, tableting molding, or the like, and used as they are, or if necessary, crushed to an appropriate size.
As a molding method, a dry method or a wet method can be used, in which case a small amount of water, a lubricant or the like may be used.

Further, as nickel-based catalysts, for example, steam shift catalyst, C11-2-03 (NiO-cement), C
11-2-06 (NiO-refractory), C11-2 (Ni
-Calcium aluminate), C11-9 (Ni-alumina); hydrogenation catalyst, C46-7 (Ni-diatomaceous earth), C
46-8 (Ni-silica), C36 (Ni-Co-Cr)
-Alumina); gasification catalyst, XC99 (NiO); hydrogenation shift catalyst, C20-7 (Ni-Mo-alumina) [above, Toyo CCI Co., Ltd.] and hydrogenation catalyst, N-11
1 (Ni-diatomaceous earth); gasification shift catalyst, N-174 (N
iO); various products such as gasification catalyst, N-185 (NiO) [above, manufactured by JGC Corporation] are commercially available, and an appropriate one may be selected and used from these. There are various methods for obtaining copper oxides. For example, copper nitrates, sulfates, chlorides, organic acid salts, etc. are added with alkalis such as caustic soda, caustic potash, sodium carbonate, and ammonia to form oxides. There is a method of precipitating the intermediate of 1 and calcining the obtained precipitate. These are usually formed into a molded product by extrusion molding, tableting molding, or the like, and used as they are, or if necessary, crushed to an appropriate size. As a molding method, a dry method or a wet method can be used, in which case a small amount of water, a lubricant or the like may be used. Further, since there are various commercially available copper oxide catalysts, those selected from them may be used.

The point is that reduced nickel, nickel oxide, reduced copper, copper oxide, etc. are finely dispersed and have a large surface area and high contact efficiency with gas. The specific surface area of these nickel or copper catalysts is usually
In the range of 10 to 300 m ² / g by the BET method, it is preferably in the range of 30~250m ² / g. Also,
The content of nickel or copper is usually 5 to 95 wt%, preferably 20 to 95 wt% in terms of metallic nickel or copper.
%. When the content of nickel or copper is less than 5 wt%, the deoxidizing ability becomes low, and 95 wt%
If it is higher than this, sintering may occur during the reduction with hydrogen and the activity may be reduced.

Silicification of nickel or copper can usually be carried out by bringing silane into contact with reduced nickel, nickel oxide, reduced copper, copper oxide or the like. In the case of nickel oxide, copper oxide, etc. Reduced nickel or reduced copper may be obtained by hydrogen reduction. Hydrogen reduction can be carried out by passing a hydrogen-nitrogen mixed gas at a hollow cylinder linear velocity (LV) of about 5 cm / sec at a temperature of 350 ° C. or lower, but care must be taken so that the temperature does not rise sharply because it is an exothermic reaction. is there. In addition, silicidation can be carried out simultaneously by carrying out the reduction with hydrogen-based silane, which is convenient.

Silicification is usually carried out by filling a cylinder such as a refining cylinder with nickel, copper, or those obtained by supporting these on a carrier,
This is done by passing silane or a silane-containing gas through this. The concentration of silane used for silicidation is usually 0.1% or more, preferably 1% or more. If the silane concentration is lower than 0.1%, it takes time to complete the reaction, which is uneconomical. Although silicidation can be carried out at room temperature, it is an exothermic reaction and the temperature tends to rise as the silane concentration increases, so the gas flow rate is adjusted so that it is usually maintained at 200 ° C or lower, preferably 100 ° C or lower. It is preferable to do so. The end of silicidation can be known by a decrease in the calorific value and an increase in the outflow amount of silane from the outlet of the cylinder. In the present invention, siliconized nickel or copper may be charged again into another purification column, and crude germanium hydride may be passed through this to purify oxygen, but the silicon compound is highly toxic and should be handled with great care. Therefore, it is preferable that the silicidation is performed from the beginning in a germanium hydride purification column, and after completion of the silicidation, crude germanium hydride is subsequently supplied to perform oxygen removal purification.

Purification of germanium hydride is usually carried out by flowing crude germanium hydride through a purification column filled with a silicide of nickel or copper, and the germanium hydride comes into contact with the silicide of nickel or copper. As a result, oxygen contained as an impurity in the crude germanium hydride is removed. The oxygen concentration in the crude germanium hydride applied to the present invention is usually 100 ppm or less. If the oxygen concentration is higher than this, the amount of heat generated increases, so heat removal means is required depending on the conditions. The filling length of the nickel or copper silicide that is filled in the purifying cylinder is
In practice, it is usually 50 to 1500 mm. Filling length is 5
If it is shorter than 0 mm, the oxygen removal rate may be lowered, and if it is longer than 1500 mm, the pressure loss may be too large. The vacant linear velocity (LV) of crude germanium hydride at the time of purification varies depending on the oxygen concentration in the supplied germanium hydride and operating conditions and cannot be specified unconditionally, but it is usually 100 cm / sec or less, preferably 30 cm / sec. It is below. The contact temperature between germanium hydride and a silicide of nickel or copper is the temperature of the gas supplied to the inlet of the purifying cylinder, which is about 200 ° C. or lower, preferably 100 ° C. or lower. do not need. Atmospheric pressure is not particularly limited to the pressure, vacuum, although it is possible either process the pressure is usually 20 kg / cm ² abs or less, preferably 0.1~10kg / cm ² abs.

Further, even if a small amount of water is contained in germanium hydride, it does not have a bad influence on the deoxidizing ability, and when a carrier is used, the water is also removed at the same time depending on the kind. To be done. In the present invention, in the oxygen removal step using a silicide of nickel or copper,
If necessary, it is possible to appropriately combine the steps of removing water with a dehumidifying agent such as synthetic zeolite, whereby water is completely removed, and purified germanium hydride having an extremely high purity can be obtained.

[0013]

【Example】

Example 1 (Reduction treatment of nickel) A commercially available nickel catalyst (N-111, manufactured by JGC Corporation) was used. The composition of this product is N
i + NiO form, 45-47 wt% as Ni,
Cr 2-3 wt%, Cu 2-3 wt%, diatomaceous earth 27-2
9 wt% and graphite 4-5 wt%, specific surface area 150 m
² / g, which is a molded body having a diameter of 5 mm and a height of 4.5 mm. 63 ml of this nickel catalyst crushed to 8 to 10 mesh was filled in a stainless steel purification cylinder having an inner diameter of 16.4 mm and a length of 400 mm with a filling length of 300 mm (filling density:
1.0 g / ml). Hydrogen at a temperature of 150 ° C. and a flow rate of 456 ml / min (LV = 3.6 cm)
/ Sec) for 3 hours and then cooled to room temperature. (Siliconide of nickel) Hydrogen containing 10 vol% of silane was supplied to this purification column at 380 cc / min (LV = 3 c).
m / sec), and nickel was silicified.
At this time, the room temperature was 25 ° C., but the temperature of the outlet gas of the cylinder rose to about 80 ° C. due to the heat generated by siliconization. After that, the temperature of the outlet gas gradually decreased, and after 1.5 hours, the temperature returned to room temperature and the silicidation treatment was completed. As it was, a nitrogen purge was further performed for 3 hours to prepare for the purification of germanium hydride. (Purification of germanium hydride) Subsequently, germanium hydride was purified. 1 vol% germanium hydride and 0.50 ppm as impurities in this purification column
Of hydrogen-containing crude germanium hydride containing oxygen at a temperature of 1266 cc / min (LV = 10 cm / min) at room temperature (20 ° C.) was used and a yellow phosphorus luminescence type oxygen analyzer (lower limit concentration 0.01 ppm) was used. When I measured it,
Oxygen was not detected and was 0.01 ppm or less. 100 minutes after the purification was started, the oxygen concentration in the outlet gas was 0.01 ppm or less even when the gas flow rate was increased four times.

Example 2 Commercially available copper oxide catalyst (Nissan Gardler Co., Ltd., G10)
8) was used. This product uses SiO ₂ as a carrier, has a Cu content of 30%, and has a diameter of 5 mm and a height of 4.5.
It is a molded body of mm. This copper oxide catalyst is 8-10 mes
63 ml crushed into h, inner diameter 19 ml, length 400
A stainless steel purification cylinder of mm was filled with a filling length of 300 mm (filling density 1.0 g / ml). (Silicone of copper) 380 cc / min (LV = 3 cm / s) of hydrogen containing 10 vol% of silane was added to this purification column.
In ec), nickel was silicified. At this time, the room temperature was 25 ° C., but the temperature of the outlet gas of the cylinder rose to about 85 ° C. due to the heat generated by siliconization. After that, the temperature of the outlet gas gradually decreased, and after 3 hours, the temperature returned to room temperature and the silicidation treatment was completed. As it was, a nitrogen purge was further performed for 3 hours to prepare for the purification of germanium hydride. (Purification of germanium hydride) Subsequently, germanium hydride was purified. 12 hydrogen-based crude germanium hydride containing 1 vol% germanium hydride and 0.50% oxygen as an impurity was added to the purification column.
When oxygen was not detected when measured using a yellow phosphorus luminescence type oxygen analyzer (lower limit concentration of 0.01 ppm) at a room temperature (20 ° C.) at a rate of 66 cc / min (LV = 10 cm / min), 0.01 ppm was not detected. It was below. 100 minutes after the purification was started, the oxygen concentration in the outlet gas was 0.01 ppm or less even when the gas flow rate was increased four times.

Comparative Example 1 Activated carbon (coconut shell charcoal) was crushed to 8 to 24 mesh, and 35 g of the same was placed in the same purification cylinder as in Example 1.
After filling (filling density 0.57 g / ml) and heat-treating at 270 to 290 ° C. for 4 hours in a helium stream, it was cooled to room temperature. The same amount of germanium hydride as used in Example 1 (1 vol%) and 0.50 ppm as impurities in this purification column
Hydrogen-based crude germanium hydride containing oxygen was flowed at room temperature at a rate of 1266 cc / min (LV = 10 cm / min) and measured using a yellow phosphorescence oxygen analyzer (lower limit concentration 0.01 ppm). , 0.50p
It was pm, and in this state, the oxygen concentration was kept flowing for 2 hours, but no change in oxygen concentration was observed.

Example 3 (Siliconization of nickel) In the same manner as in Example 1, reduced nickel was prepared in a purifying cylinder, and 100% silane was added thereto.
Nickel was siliconized by flowing it at 8 cc / min (LV = 0.3 cm / sec) for 2 hours. (Purification of germanium hydride) 1266 cc / m of the same crude germanium hydride used in Example 1 was added to this purification column.
Yellow phosphorescent oxygen analyzer (lower limit concentration 0.01ppm) by flowing at room temperature at a speed of in (LV = 10cm / min)
Oxygen was not detected when measured using
It was pm or less. I continued to run for 10 hours in this state,
The oxygen concentration of the outlet gas was 0.01 ppm or less.

Example 4 (Siliconization of Nickel) In the same manner as in Example 1, reduced nickel was prepared in a purifying cylinder, and 10% silane nitrogen was added thereto at 380 cc / min (LV = 3 cm / sec). The silicon was flown for 3 hours to silicify nickel. (Purification of germanium hydride) 2 vol% germanium hydride and 0.75 ppm as impurities in this purification column
Nitrogen-based crude germanium hydride containing oxygen is flowed at room temperature (20 ° C.) at a rate of 1266 cc / min (LV = 10 cm / min) and a yellow phosphorous emission oxygen analyzer (lower limit concentration 0.01 ppm) is used. When I measured it,
Oxygen was not detected and was 0.01 ppm or less. Flowing was continued for 10 hours in this state, but the oxygen concentration of the outlet gas was 0.
It was less than 01 ppm.

Example 5 (Preparation of nickel catalyst) Al (NO ₃ ) ₃ 9 in ₃ L of water
H ₂ O (454 g) was dissolved and cooled to 5 to 10 ° C. in an ice bath. Add 200 g of NaOH to this with vigorous stirring.
Was dissolved in 1 L of water and cooled to 5 to 10 ° C, and the solution was added dropwise over 2 hours to obtain sodium aluminate. next,
_{Ni (NO 3) 2 · 6H} 2 O, the 101g was dissolved in water of 600 ml, this was added concentrated nitric acid 45 ml 5 to 10
What was cooled to 0 ° C was added to the sodium aluminate solution over 1 hour with vigorous stirring. The resulting precipitate was filtered, and the precipitate thus obtained was stirred in 2 L of water for 15 minutes and washed to obtain neutrality by repeating 6 times. The resulting precipitate was subdivided, dried in an air bath at 105 ° C. for 16 hours, then ground, and sieved to collect 12 to 24 mesh. This contained 29.5 wt% nickel oxide (NiO). (Reduction treatment of nickel) 63 ml of this was packed in the same purification cylinder as used in Example 1 (packing density: 0.77 g
/ Ml), hydrogen at a temperature of 350 ° C. and a flow rate of 12
After performing reduction treatment by flowing at 3 cc / min (LV = 1 cm / sec) for 16 hours, siliconization of nickel was performed under the same conditions as in Example 1. (Purification of germanium hydride) Subsequently, germanium hydride was purified. 1266 cc / m of the same crude germanium hydride used in Example 1 was added to this purification column.
Room temperature (20) at a speed of in (LV = 10 cm / min)
Yellow phosphorous emission type oxygen analyzer (lower limit concentration of measurement: 0.
Oxygen was not detected and was 0.01 ppm or less. Flowing was continued for 10 hours in this state, but the oxygen concentration of the outlet gas was 0.01 ppm or less.

Example 6 (Preparation of Copper Oxide Catalyst) To a 20 wt% aqueous solution of copper sulfate, 20 wt% of sodium carbonate was added until the pH was adjusted to 9 to 10 to precipitate crystals of basic copper carbonate. The crystals were repeatedly filtered, washed and dried in an air stream at 130 ° C.
It baked at 0 degreeC and produced the copper oxide. Alumina sol (Cataloid-A manufactured by Catalysts & Chemicals Co., Ltd.) was added to the copper oxide.
S-2) was mixed and kneaded with a kneader. Then, it was dried in air at 130 ° C. and further calcined at 350 ° C., and the calcined product was crushed into granules. This product was formed into a cylindrical pellet having a diameter of 6 mm and a height of 4 mm by tableting. This was crushed and shaken to collect 12 to 24 mesh. (Silicone of copper) 63 ml (100 g, packing density 1.6 g / m 2) of the same was used in the same purifying cylinder as used in Example 1.
l) Fill with nitrogen containing 10 vol% of silane at 380 cc / min (LV = 3 cm / sec).
The silicon was silicified by flowing for a time. (Purification of germanium hydride) 1266 cc / m of the same crude germanium hydride used in Example 1 was added to this purification column.
Room temperature (20) at a speed of in (LV = 10 cm / min)
When the oxygen concentration was measured by flowing it at (° C.), oxygen was not detected and was 0.01 ppm or less. Flowing was continued for 10 hours in this state, but the oxygen concentration of the outlet gas was 0.01 ppm or less.

[0020]

Industrial Applicability According to the present invention, it is possible to remove oxygen in germanium hydride, which has been difficult to remove conventionally, to an extremely low concentration of 0.1 ppm or less, and further 0.01 ppm or less. It has become possible to obtain the ultra-high-purity purified germanium hydride that has been demanded by the above.

Claims (3)

[Claims] 1. A method for purifying germanium hydride, which comprises contacting crude germanium hydride with a silicide of nickel or copper to remove oxygen contained in the crude germanium hydride. 2. The method for purifying germanium hydride according to claim 1, wherein the silicide of nickel or copper is obtained by bringing nickel or copper into contact with silane. 3. The contact temperature between crude germanium hydride and a silicide of nickel or copper is 200 ° C. or lower.
The method for purifying germanium hydride according to 1.