CA1189286A - Process for purifying chlorosilanes - Google Patents
Process for purifying chlorosilanesInfo
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- CA1189286A CA1189286A CA000393042A CA393042A CA1189286A CA 1189286 A CA1189286 A CA 1189286A CA 000393042 A CA000393042 A CA 000393042A CA 393042 A CA393042 A CA 393042A CA 1189286 A CA1189286 A CA 1189286A
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- Prior art keywords
- chlorosilane
- compounds
- compound
- boron
- hydrogen
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/08—Compounds containing halogen
- C01B33/107—Halogenated silanes
- C01B33/10778—Purification
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Abstract
ABSTRACT OF THE DISCLOSURE:
The present invention relates to a process for purifying chlorosilanes of impurities contained therein. These impurities are boron compounds and compound of metals. This process is characterized in that the chlorosilanes in liquid phase are brought into intimate contact with a compound which contains one or several Si-O-Si linkages in the presence of hydrogen halide and subsequently the chlorosilane thus purified is separated from the non-volatile boron or metal compounds thereby formed by distillation. Purified SiHCl3 according the within process is needed to manufacture polycrystalline or monocrystalline silicon which is used for semi-conductor purposes. Purified SiCl4 without metal compounds is needed for the production of optical filaments.
The present invention relates to a process for purifying chlorosilanes of impurities contained therein. These impurities are boron compounds and compound of metals. This process is characterized in that the chlorosilanes in liquid phase are brought into intimate contact with a compound which contains one or several Si-O-Si linkages in the presence of hydrogen halide and subsequently the chlorosilane thus purified is separated from the non-volatile boron or metal compounds thereby formed by distillation. Purified SiHCl3 according the within process is needed to manufacture polycrystalline or monocrystalline silicon which is used for semi-conductor purposes. Purified SiCl4 without metal compounds is needed for the production of optical filaments.
Description
The object of the p~es~nt invention is a process for purifying c~lorosilanes which are made impure by boron, metal compounds and hydrogen silanes. It is possible ~7ith the aid of this process to remcve these impurities from the chlorosilanes to such an extent that boron is no longer detectable in the purified chlorosilanes by known analytic methods and that the content of the other metal compounds is less than 10 ppb~
To manufacture polycrystalline or monocrystalline silicon which is used for semi-conductor purposes, an extremely pure metallic silicon is needed. The refining of silicon for the manufacture of semiconductors is done generally by zone-melting. According to this process almost all elements contained therein in trace form can be removed from the already very pure transistor silicon Thls method is not suitable for removing boron however, us this element has a distribution coefficient of approximately 1 both in the silicon melt and in the stable phase. Therefore, special emphasis must be placed on removing boron impurities as completely as possible at -the preliminary stage, e.g. from the trichlorosilane, prior to its reduction to a transistor silicon. Remaining boron concentrations of 0.1 ppb in trichlorosilane are to be aimed for.
SiC14, in highly purified form, is a raw material in great demand for the production of optical fibres [light-wave conductors). The elements Fe, Co, Ni, Cu, Cr, V, Mn interfere with this application since they absorb in the wave-length range ~1000 nm, thus damping the light-energy produced and impairing the light-transmission performance in an unwan-ted manner, to the point of making the ~ibres useless. In addition to this, hydrogen chlorosilanes are detrimental even in the lowest concentrations, even in the ppm range, for example, since, during oxidative conversion of SiC14 into SiO2 by conventional 21~
methods, they giVe wise to stu~bo~n retention of hyd~oxyl groups in the SiO2. The result of this us that the light-transmission quality of the fibres may be substantiallY
reduced in the ~900 nm range. on the case of light~conducting fires to be used industrially for communication purposes in this wave-length range, it is ~ndispensible that the interference factors described above be eliminated, No satisfactory results can be achieved using disk tillation purification methods alone. Several other chemical purification methods have already been tried: for example processes have been described where the high reactivity of boron compounds with organic -functional groups is used by adding to boron~containing chlorosilanes small quantities of organic material as complexing agents, for example, mannite or other sugar alcohols, ketones, amino compounds and many others. These methods indicated certain results with boron compounds, but led to new problems with carbon impurities, which signifies a considerable disadvantage.
It was also proposed to blow into boron-containing chlorosilanes inert gases, e.g, argon or hydrogen containing traces oE moisture. This process however causes great problems through tenacious siliciEication particularly at the inlet point and, in addition, because of awkward neu-tral gas loading of product coolers and distillation columns, leads to procluct losses because of high partial pressure of e.g.
trichlorosilane problems.
Other attempts at purification were made with the aid of chromatographic methods using various adsorption agents it solid beds e.g. silica gels, aluminium oxides, ion exchangers, nylon powder etc. All of these adsorption processes are discarbed partly due to a too low purification capacity ~e.g.
silica gels), also partly due to entry of carbon (e.g. when
To manufacture polycrystalline or monocrystalline silicon which is used for semi-conductor purposes, an extremely pure metallic silicon is needed. The refining of silicon for the manufacture of semiconductors is done generally by zone-melting. According to this process almost all elements contained therein in trace form can be removed from the already very pure transistor silicon Thls method is not suitable for removing boron however, us this element has a distribution coefficient of approximately 1 both in the silicon melt and in the stable phase. Therefore, special emphasis must be placed on removing boron impurities as completely as possible at -the preliminary stage, e.g. from the trichlorosilane, prior to its reduction to a transistor silicon. Remaining boron concentrations of 0.1 ppb in trichlorosilane are to be aimed for.
SiC14, in highly purified form, is a raw material in great demand for the production of optical fibres [light-wave conductors). The elements Fe, Co, Ni, Cu, Cr, V, Mn interfere with this application since they absorb in the wave-length range ~1000 nm, thus damping the light-energy produced and impairing the light-transmission performance in an unwan-ted manner, to the point of making the ~ibres useless. In addition to this, hydrogen chlorosilanes are detrimental even in the lowest concentrations, even in the ppm range, for example, since, during oxidative conversion of SiC14 into SiO2 by conventional 21~
methods, they giVe wise to stu~bo~n retention of hyd~oxyl groups in the SiO2. The result of this us that the light-transmission quality of the fibres may be substantiallY
reduced in the ~900 nm range. on the case of light~conducting fires to be used industrially for communication purposes in this wave-length range, it is ~ndispensible that the interference factors described above be eliminated, No satisfactory results can be achieved using disk tillation purification methods alone. Several other chemical purification methods have already been tried: for example processes have been described where the high reactivity of boron compounds with organic -functional groups is used by adding to boron~containing chlorosilanes small quantities of organic material as complexing agents, for example, mannite or other sugar alcohols, ketones, amino compounds and many others. These methods indicated certain results with boron compounds, but led to new problems with carbon impurities, which signifies a considerable disadvantage.
It was also proposed to blow into boron-containing chlorosilanes inert gases, e.g, argon or hydrogen containing traces oE moisture. This process however causes great problems through tenacious siliciEication particularly at the inlet point and, in addition, because of awkward neu-tral gas loading of product coolers and distillation columns, leads to procluct losses because of high partial pressure of e.g.
trichlorosilane problems.
Other attempts at purification were made with the aid of chromatographic methods using various adsorption agents it solid beds e.g. silica gels, aluminium oxides, ion exchangers, nylon powder etc. All of these adsorption processes are discarbed partly due to a too low purification capacity ~e.g.
silica gels), also partly due to entry of carbon (e.g. when
2~6 using ion exchangers or nylon) into the silicon. The task is therefore to Eind a process with the aid of which it is possible to remove boron, metal compounds and/or hydrogen silanes from chlorosilanes as quantitatively as possible, which is simple to use and requires no additional expendikure on apparatus or introduces any additional substances into the ch]orosilane. The chlorosilane thereby obtained will have a boron content which is 0.1 ppb boron. As these small quantities can no longer be determined by analysis, the stipulation that a decompensated electronic grade silicon manufactured from the chlorosilane will have a resistance of 9,000 cm or more is applicable to the boron contentO
Furthermore the chlorosilane to be obtained shall have a content of ions of heavy metal which is less than 10 ppb.
When SiC14 in to be purified, this shall have a con-ten-t of hvdrogen-silanes of less than 1 ppm.
In accordance with the present invention there is provided a method for removing from a chlorosilane, boron, metal compounds, hydrogensilanes and mixtures thereof con-tained in the chlorosilane as impurities, characterized in that the chlorosilane is brought, in the liquid phase, into (i) into intimate contact with a compound soluble in said chlorosilane and containing one or more Si - O - Si groups, in the presence of 0.005 to 0.1% by weight relative to the chlorosilane of hydrogen-halide, the chlorosilane thus purified being then separated from the resulting less-volatile compound or compounds, said less-volatile compound or compounds being soluble in the chloro-silane, the separation of the less-volatile com-pound or compounds being effected by distillation, or (ii) into intimate contact with SiO2, in the presence 2~3~
of 0.005 to 0.1~ by weight, relative to the chlorosilane, of hydrogen-halide, the chloro-silane thus purified being then separated from the SiO2.
In accordance with the present invention the treatment with the compound containing the Si - O - Si groups may be carried out at a temperature of from 0C to 30C.
The present invention also provides a method for removing from a chlorosilane, boron, metal compounds, hydrogensilanes and mixtures thereof contained in the chloro-silane as impurities, characterized in that, at a temperature of from 0C to 30C, the chlorosilane is brought, in -the liquid phase, into intimate contact with a compound soluble in said chlorosilane and containing one or more Si - O - Si bonds, in amounts equal to or greater than 0O005~ by weight relative to the chlorosilane, in the presence of 0.005 to 0.1~ by weight, relative to the chlorosilane, of hydrogen-halide, the chlorosilane thus purified being then separated from the resulting less-volatile compound or compounds, sa:id less-volatile compound or compounds being soluble in the chlorosilane, the separation of the less-volatile compound or compounds being eEfected by distillation.
The present invention further provides a method for removing from a chlo~osilane, boron, metal compounds, hydrogensilanes and mixtures thereof contained in the chloro-silane as impurities, characterized in that, at a temperature ox from 0C to 30C, the chlorosilane is brought, in the liquid phase, into intimate contact with a compound soluble in said chlorosilane and containing one or more Si - O Si groups, in amounts of 0.005 to 0.1% by weight relative to the chlorosilane, in the presence of 0.005 to 0.1% by weight, relative to the chlorosilane, ox hydrogen-halide, the chloro-. .,, 3a -l92~3 Ei silane thus purlfied being then separated from the resulting less-volatile compounds or compounds, said less-volatile compound or compounds being soluble in the chlorosilane, the separation of the less-volatile compound or compounds being effected by distillation.
In accordance with the present invention the hydrogen halide may be hydrochloric acid.
In accordance with the invention the compound con-taining the Si - O - Si groups may be produced in situ by contacting the liquid chlorosilane with hydrochloric acid.
The hydrochloric acid may have a concentration above 1.050 g/l for such contacting.
The present invention further provides a method for removing from a chlorosilane, boron, metal compounds, hydrogensilanes and mixtures thereof contained in the chloro-silane as impurities, characterized in that, at a temperature of from 0C to 30C, the chlorosilane is brought, in the liquid phase, into intimate contact with SiO2 in a chromato-graphic column, in amounts equal to or greater than 0.005-- by weight relative to the chlorosilane, in the presence of 0.005 to 0.1% by weight, relative to the chlorosilane, of hydrogen--halide, the chlorosilane thus purified being then separated from the SiO2.
The present invention also provides a method for removing, from a chlorosilane, boron, metal compounds, hydrogensilanes and mixtures thereof contained in the chloro-silane as impurities, characterized in that, at a temperature of from 0C to 30C, the chlorosilane is brought, in the liquid phase, into intimate contact with SiO2~ in amounts equal to or greater than 0.005% by weight relative to the chlorosilane, in the presence of 0.005 to 0.1% by weight, relative to the chlorosilane, of hydrogen-halide, the chloro-- 3b -2~3~
silane thus purified being then separated from the SiO2.
In accordance with the invention finely divided SiO2 may be used.
It is possible with the aid of the procedure according to the invention to obtain a chlorosilane in which no boron can be detected in the silane as refined by any known, analytical method. No boron can be detected with the aid of both colorimetric and spectroscopic methods. The resistance crucial to the classification as transistor silicon of the quality of the semi-conductor produced from silane purified according to the invention and purified in the zone melting process is at least 9,000 Q cm.
- 3c -8~6 when SiC14 is purified my the procedure according to the invention, surprisingly enough it no longer contains any SiHC13. Under the conditions according Jo the invention, the trichlorosilane reacts with tke siloxane and remains, during subsequent distillation, in oligomeric or polymeric form, in the bottom. This produces a tetrachlorosilane from which optical fibres of the required high quality can be produced.
The method of the invention is distinguished by an extremely simple operation; for example it is sufficient to introduce the constituents to be used according to the invention into the chlorosilane in a way known in itself and to take pre-cuations that an homogenous distribution of the compounds in the chlorosilane takes place. The reaction of the boron compounds with the compounds to be added may occur at room temperature so that heating is not necessary. The resulting boron-containing product of the reaction is soluble in the chlorosilanes of the resulting concentrations and non-volatile.
It can then be easily separated from the latter by distillation of the chlorosilanes whereby it stays at the bottom.
The quantity of the compounds used with at least one Si-O-Si group depends on the boron content in the chlorosilane. It will correspond to at leas-t one boron equivalent, i.e. to one third of a mole of the boric compound present as an impurity. This means that for one B-bond there is at least one Si-O-Si group. The theoretically usable quantity, which in practice has a purifying effect, is however so small that in practice an excess of up to one hundred times the theoretical quantity is recommended. With the normal boron and heavy me-tal content in chlorosilanes at between 1 and 50 ppm, this means that the addition of compounds with Si-O-Si groups, is between 0.005 and 0.1% by weight, related to the chlorosilane. With greater quantities of impurities !, ?~
8~
corresponding greater quantities of compounds containing Si~-Si groups must be used.
The reaction of the boxon and metal impurities with the added agents, according to the invention, occurs only in the presence of hydrogen halides. The preferred hydrogen halide is hydrogen chloride. The latter is either added in measured quantities together with the compounds containing the Si-O-Si groups or it is already dissolved in the chlorosilane.
The necessary quantity of hydrogen halide is in the same order of magnitude as the quantity of Si-O~Si groups.
To toe compounds with Si-O-Si groups belong malnly tetrachlorodisiloxane and its higher homologues e.g. he~achloro-disiloxane,hexachlorotrisiloxane or octachlorotrisiloxane or mixtures of these compounds. However other siloxanes may be used, according to the invention, which are free of organo groups and volatile or stable at room temperature.
Furthermore, according to the invention, suitable compoudns are those which have an Si-O- layer lattice or space lattice e.g. silicoformic anhydride or even SiO2. The latter can be used both in the highly-dispersed form of the so-called ~yrogenic silicic acid and in the coarser form of silica gels.
Use of SiO2 in the form of a silica gel as usecl in column chromatography yields a special finished product of the process according to the invention: the chlorosilane with boron and/or other impurities which contains small quantities of hydrogen chloride is allowed to run through a silica gel column. Boron and metal compounds thereby arising remain in the column so that e.g. a boron-free eluate is obtained. It can be proved with the aid of the finished product that during purification, according to the invention, the presence of hydrogen halides is necessary: if the chloro-~5-
Furthermore the chlorosilane to be obtained shall have a content of ions of heavy metal which is less than 10 ppb.
When SiC14 in to be purified, this shall have a con-ten-t of hvdrogen-silanes of less than 1 ppm.
In accordance with the present invention there is provided a method for removing from a chlorosilane, boron, metal compounds, hydrogensilanes and mixtures thereof con-tained in the chlorosilane as impurities, characterized in that the chlorosilane is brought, in the liquid phase, into (i) into intimate contact with a compound soluble in said chlorosilane and containing one or more Si - O - Si groups, in the presence of 0.005 to 0.1% by weight relative to the chlorosilane of hydrogen-halide, the chlorosilane thus purified being then separated from the resulting less-volatile compound or compounds, said less-volatile compound or compounds being soluble in the chloro-silane, the separation of the less-volatile com-pound or compounds being effected by distillation, or (ii) into intimate contact with SiO2, in the presence 2~3~
of 0.005 to 0.1~ by weight, relative to the chlorosilane, of hydrogen-halide, the chloro-silane thus purified being then separated from the SiO2.
In accordance with the present invention the treatment with the compound containing the Si - O - Si groups may be carried out at a temperature of from 0C to 30C.
The present invention also provides a method for removing from a chlorosilane, boron, metal compounds, hydrogensilanes and mixtures thereof contained in the chloro-silane as impurities, characterized in that, at a temperature of from 0C to 30C, the chlorosilane is brought, in -the liquid phase, into intimate contact with a compound soluble in said chlorosilane and containing one or more Si - O - Si bonds, in amounts equal to or greater than 0O005~ by weight relative to the chlorosilane, in the presence of 0.005 to 0.1~ by weight, relative to the chlorosilane, of hydrogen-halide, the chlorosilane thus purified being then separated from the resulting less-volatile compound or compounds, sa:id less-volatile compound or compounds being soluble in the chlorosilane, the separation of the less-volatile compound or compounds being eEfected by distillation.
The present invention further provides a method for removing from a chlo~osilane, boron, metal compounds, hydrogensilanes and mixtures thereof contained in the chloro-silane as impurities, characterized in that, at a temperature ox from 0C to 30C, the chlorosilane is brought, in the liquid phase, into intimate contact with a compound soluble in said chlorosilane and containing one or more Si - O Si groups, in amounts of 0.005 to 0.1% by weight relative to the chlorosilane, in the presence of 0.005 to 0.1% by weight, relative to the chlorosilane, ox hydrogen-halide, the chloro-. .,, 3a -l92~3 Ei silane thus purlfied being then separated from the resulting less-volatile compounds or compounds, said less-volatile compound or compounds being soluble in the chlorosilane, the separation of the less-volatile compound or compounds being effected by distillation.
In accordance with the present invention the hydrogen halide may be hydrochloric acid.
In accordance with the invention the compound con-taining the Si - O - Si groups may be produced in situ by contacting the liquid chlorosilane with hydrochloric acid.
The hydrochloric acid may have a concentration above 1.050 g/l for such contacting.
The present invention further provides a method for removing from a chlorosilane, boron, metal compounds, hydrogensilanes and mixtures thereof contained in the chloro-silane as impurities, characterized in that, at a temperature of from 0C to 30C, the chlorosilane is brought, in the liquid phase, into intimate contact with SiO2 in a chromato-graphic column, in amounts equal to or greater than 0.005-- by weight relative to the chlorosilane, in the presence of 0.005 to 0.1% by weight, relative to the chlorosilane, of hydrogen--halide, the chlorosilane thus purified being then separated from the SiO2.
The present invention also provides a method for removing, from a chlorosilane, boron, metal compounds, hydrogensilanes and mixtures thereof contained in the chloro-silane as impurities, characterized in that, at a temperature of from 0C to 30C, the chlorosilane is brought, in the liquid phase, into intimate contact with SiO2~ in amounts equal to or greater than 0.005% by weight relative to the chlorosilane, in the presence of 0.005 to 0.1% by weight, relative to the chlorosilane, of hydrogen-halide, the chloro-- 3b -2~3~
silane thus purified being then separated from the SiO2.
In accordance with the invention finely divided SiO2 may be used.
It is possible with the aid of the procedure according to the invention to obtain a chlorosilane in which no boron can be detected in the silane as refined by any known, analytical method. No boron can be detected with the aid of both colorimetric and spectroscopic methods. The resistance crucial to the classification as transistor silicon of the quality of the semi-conductor produced from silane purified according to the invention and purified in the zone melting process is at least 9,000 Q cm.
- 3c -8~6 when SiC14 is purified my the procedure according to the invention, surprisingly enough it no longer contains any SiHC13. Under the conditions according Jo the invention, the trichlorosilane reacts with tke siloxane and remains, during subsequent distillation, in oligomeric or polymeric form, in the bottom. This produces a tetrachlorosilane from which optical fibres of the required high quality can be produced.
The method of the invention is distinguished by an extremely simple operation; for example it is sufficient to introduce the constituents to be used according to the invention into the chlorosilane in a way known in itself and to take pre-cuations that an homogenous distribution of the compounds in the chlorosilane takes place. The reaction of the boron compounds with the compounds to be added may occur at room temperature so that heating is not necessary. The resulting boron-containing product of the reaction is soluble in the chlorosilanes of the resulting concentrations and non-volatile.
It can then be easily separated from the latter by distillation of the chlorosilanes whereby it stays at the bottom.
The quantity of the compounds used with at least one Si-O-Si group depends on the boron content in the chlorosilane. It will correspond to at leas-t one boron equivalent, i.e. to one third of a mole of the boric compound present as an impurity. This means that for one B-bond there is at least one Si-O-Si group. The theoretically usable quantity, which in practice has a purifying effect, is however so small that in practice an excess of up to one hundred times the theoretical quantity is recommended. With the normal boron and heavy me-tal content in chlorosilanes at between 1 and 50 ppm, this means that the addition of compounds with Si-O-Si groups, is between 0.005 and 0.1% by weight, related to the chlorosilane. With greater quantities of impurities !, ?~
8~
corresponding greater quantities of compounds containing Si~-Si groups must be used.
The reaction of the boxon and metal impurities with the added agents, according to the invention, occurs only in the presence of hydrogen halides. The preferred hydrogen halide is hydrogen chloride. The latter is either added in measured quantities together with the compounds containing the Si-O-Si groups or it is already dissolved in the chlorosilane.
The necessary quantity of hydrogen halide is in the same order of magnitude as the quantity of Si-O~Si groups.
To toe compounds with Si-O-Si groups belong malnly tetrachlorodisiloxane and its higher homologues e.g. he~achloro-disiloxane,hexachlorotrisiloxane or octachlorotrisiloxane or mixtures of these compounds. However other siloxanes may be used, according to the invention, which are free of organo groups and volatile or stable at room temperature.
Furthermore, according to the invention, suitable compoudns are those which have an Si-O- layer lattice or space lattice e.g. silicoformic anhydride or even SiO2. The latter can be used both in the highly-dispersed form of the so-called ~yrogenic silicic acid and in the coarser form of silica gels.
Use of SiO2 in the form of a silica gel as usecl in column chromatography yields a special finished product of the process according to the invention: the chlorosilane with boron and/or other impurities which contains small quantities of hydrogen chloride is allowed to run through a silica gel column. Boron and metal compounds thereby arising remain in the column so that e.g. a boron-free eluate is obtained. It can be proved with the aid of the finished product that during purification, according to the invention, the presence of hydrogen halides is necessary: if the chloro-~5-
3$~
silane contains no dissolved hYd~Qchloric acid then the eluate is made impure still fur~he~ by ~o~ic compounds which cannot be sepaxated my ~ractiona~ distil~a-tion.
- It is, according to the invention, further possible to produce the siloxane usable for purification it situ from the chlorosilanes so that the siloxanes do not have to be added, but only those substances which react with the chloror silane during the formation of chlorosiloxanes and, if necessary, hydrogen chloride. An example of one of these substances is hydrochloric acid in concentrated or diluted form whereby a 10% hydrochloric acid is still suite usable. Use of hydrochloric acid has the advantage that, with the addition thereof, the quantity of hydxo~en halide necessary for the reaction with the metal compounds can be simultaneously fed in.
The quantity ox the compound to be added to the chlorosilane, which produces the siloxanes in situ, is of the same order of magnitude as the quantity of the siloxane which is added, provided that the content of boron and metal impurities in the chlorosilane lies between 1 and 50 ppm. When a greater concentration of boron impurities is to be removed, a corresponding greater quantity of hydrochloric acid or a compound with a similar effect must be used. After adding this compound, the subsequent treatment proceeds in the same manner as described above. Also no cloudiness appears in the chlorosilane in the interim period.
The process according to the invention is chiefly aimed at removing boron-containing impurities as well as impurities of the elements Fe, Co, Ni, Cu, Cr, V and Mn from trichlorosilane and tetrachlorosilane.
_ I=
_~~
This invention will be further understood by reference to the following non restrictive examples.
Example 1 To a 4 1 multiple-neck flask, in which one tube is sealed with a pierced stopper and which is also equipped with a bottom valve, an agitator and a reflux condensor surrounded by N2, were introduced 5,000 g of a typical trichlorosilane raw product, consisting of 58.4~ trichlorosilane, 41.6%
tetxachlorosilane and approximately 200 ppm hydrogen chloride with a boron content of 5.7 ppm. Under agitation at room temperature 2 ml hexachlorodisiloxane were injected through the pierced stopper with the aid of a syringe below the level of liquid in the chlorosilane mixture over a period of 3 to 4 seconds. The injected hexachlorodisiloxane was immediately dispersed in -the chlorosilanes without clouding.
The mixture was agita-ted for 30 min without under going heating and subsequently the chlorosilanes were frac-tionally distilled. In -the reamining residue of approx.
500 g SiCl~, approxO 57 ppm boron were detected.
Approx. 2.7 kg trichlorosilane and ca. 1.6 kg tetrachlorosilane in addition to approx. 200 g of intermediate fraction (mix-ture of HSiC13 and SiCl~) were produced by distilling. A silicon rod was produced Erom the trichloro-in a known manner. After the seventh zone-melting in a vacuum it has a resistance of 12200 Q cmO
Example 2 5000 g of the trichlorosilane raw product named therein were introduced into the apparatus described in Example 1. 2 ml of a suspension of 0.4 g silico-formic anhydride in tetrachlorosilane were added under agitation -to this product. This- suspension dissolved slowly in the chloro silane mixture at normal temperature. A fine dispersion was obtained which became clear within a short period.
The mixture was then agitated for 1 hour without being heated and then, similarly to Example 1, was distilled.
Ca. 2.8 kg of trichlorosilane and ca. 1.5 kg of tetrachlorosilane in addition to approx. 200 g of intermediate fraction (~SiC13/SiC14 mixture) are produced. 54 ppm of boron were analysed in the residue of ca. 500 g SiC14. (No boron could be detected by spectrometer either in the trichlorosilane distillate or in the tetrachlorosilane distillate in the 200 g of intermediate fraction).
Example 3 Example 2 ls followed except that 0.5 g pyroyenic silicic acid is added to the chlorosilane mixture. The silicic acid was dispersed over a short period of time through the entire reaction container. A slight cloudiness of SiO2 in the chlorosilanes remained throughout the process. The working up was along the lines of Example 2.
A mlnute precipitate of SiO2 with a boron content of 3860 ppm remained in the distillation residue. Another 50 ppm approx. of boron were measured in the liquid dis-tll-lation residue. No boron could be detected in any of the distillates using spectroanalytic methods.
Example 4 5000 g of trichlorosilane were introduced into the multiple-neck flask referred to ln Example 1. The trichloro-silane had a boron content of 26.4 ppm. While effecting agitation at room temperature, 1 ml of 20~ dilu-te hydrochloric acid is injected below the liquid level of the trichlorosilane through the pierced stopper with the aid of a syringe with a long needle over a period of 2 to 3 seconds. The injected hydrochloric acid disappeared without any externally visible signs of a reaction and the product in the Elask did not become cloudy but remained cleat. The t~ichlorosilane was then agitated for a further lO min approx. without being heated.
The trichlorosllane treated in this manner was then drawn off through the bottom valve into a distillation column with ca. 35 plates and all the material distilled over in a fraction (4650 g yield) at 31C. The still contained only the hold-up of the column of approx. 250 ml with a boron content of >300 ppm.
The distillate was exarnined at regular intervals both colorimetrically and spectroscopically for boron. The limit of scope of this examination was ascertained in the blank test to be 0.1 ppb and/or <50 nanogram. No boron was found in the distillate during or after distillation. Silicon rods were manufactured from the trichlorosilane obtained in a manner known in itself and purified still further by zone-melting. The measurement of the resistance of the Si-rods obtained gave values between 9200 and 10,700 so cm.
E mple 5 As in Example l, 0.~ ml of concentrated aqueous hydxochloric acid was injected into 5000 g of a typical trichlorosilane crude product, consisting of 92.6% trichloro-silane, 7.~ tetrachlorosilane and ca. 400 ppm dichloro-silane with a boron content of 1.92 ppm, whereby the hydro-chloric acid immediately dissolved without clouding. The mixture was agitated for 30 min without being heated and then the entire trichlorosilane (ca. 4550 g) was distilled over. After distillation the remaining content of the still, ca. 300 ml, consisting mainly of tetrachlorosilane, had a boron content of 518 ppm.
Blank values for boron were found in the trichloro-silane distillate regularly by colorimetric and spectro-_g_ . .
~8~
scopic analysis. the measurement ox resistance of Si-rods manufactured from thls gave values of be-tween 9700 and 11,800 Q cm.
Example 6 300 g of technical trichlorosilane, in which is dissolved 632 ppm of hydrogen chloride is fed at ca. 20C in liquid aggregate state with a flow velocity of 2.2 litre/h through a glass gas chromatographie column (diameter 50 mm, filling height 1150 mm?, filled with silica gel (pore diameter ca. 10 mm, grain size ca. 50-200 em, ASTM ca. 60-250 mesh)O
The trichlorosilane used also contained 12.4 ppm boron. After it had passed through no further traces of boron were detectable.
Polycrystalline silicon rods manufactured from trichlorosilane purified in this way gave resistance values of >10,000 Q cm.
Examples 7-14 Analogous to Example 6 a further eight 300 kg batches of boron-containing trichlorosilane with hydrogen chloride dissolved therein were fed in after each other through the same chromatographic SiO2 column already used in Example 6.
Likewise this was performed in the liquid phase:
HCl content boron content Flow velocity Example ppm ppm litre/h 7 2021 22.1 2.2 8 478 8.4 2.2 9 729 4.8 2.2 1402 11.2 2.2 11 68~ 32.5 2.2 12 275 8.2 2.2 13 1063 10.6 2.2 14 542 5.7 2.2 . .
2~
The pure trichlorosilane obtained was examined in 30 kg batches and reduced to silicon rods. In none of the 30 kg tests was boron detectable by colorimetric anal~vsis.
All silicon rods gave resistance values of >lO,OOOQcm.
The purification power of the columns used in Example 6 to Example 14 was undiminished at the comple-tion o Example 14.
Comparat ve Example In comparison to Example 6 a technical trichlorosilane with a boron content of 7.2 ppm, yet free from hydrogen chloride was used in exactly the same process. After every 120 minutes the trichlorosilane flowing out of the column was examined by colorimetric analysis for its boron content:
time trichlorosilane min discharged boron value kg 120 3.2 boron-free 240 6.5 boron-free 360 9.8 14 ppb 480 13.0 0.4 ppm 600 16.2 2.5 ppm 720 19.5 6.8 ppm Without hydrogen chloride, the column will cease to operate faultlessly after 6 hours, and will be exhausted after 10-12 hours Example 15 5 kg of tetrachlorosilane were introduced into a 4-litreagitator (mul-tiple-neck) flask made of laboratory-apparatus glass and equipped with a nitroqen cover and pierceable cap The tetrachlorosilane contained the following impurities:
copper 22 ppb nickel 48 ppb cobalt 39 ppb iron 22~ ppb manganese18 ppb chromium 28 ppb vanadium 16 ppb.
silane contains no dissolved hYd~Qchloric acid then the eluate is made impure still fur~he~ by ~o~ic compounds which cannot be sepaxated my ~ractiona~ distil~a-tion.
- It is, according to the invention, further possible to produce the siloxane usable for purification it situ from the chlorosilanes so that the siloxanes do not have to be added, but only those substances which react with the chloror silane during the formation of chlorosiloxanes and, if necessary, hydrogen chloride. An example of one of these substances is hydrochloric acid in concentrated or diluted form whereby a 10% hydrochloric acid is still suite usable. Use of hydrochloric acid has the advantage that, with the addition thereof, the quantity of hydxo~en halide necessary for the reaction with the metal compounds can be simultaneously fed in.
The quantity ox the compound to be added to the chlorosilane, which produces the siloxanes in situ, is of the same order of magnitude as the quantity of the siloxane which is added, provided that the content of boron and metal impurities in the chlorosilane lies between 1 and 50 ppm. When a greater concentration of boron impurities is to be removed, a corresponding greater quantity of hydrochloric acid or a compound with a similar effect must be used. After adding this compound, the subsequent treatment proceeds in the same manner as described above. Also no cloudiness appears in the chlorosilane in the interim period.
The process according to the invention is chiefly aimed at removing boron-containing impurities as well as impurities of the elements Fe, Co, Ni, Cu, Cr, V and Mn from trichlorosilane and tetrachlorosilane.
_ I=
_~~
This invention will be further understood by reference to the following non restrictive examples.
Example 1 To a 4 1 multiple-neck flask, in which one tube is sealed with a pierced stopper and which is also equipped with a bottom valve, an agitator and a reflux condensor surrounded by N2, were introduced 5,000 g of a typical trichlorosilane raw product, consisting of 58.4~ trichlorosilane, 41.6%
tetxachlorosilane and approximately 200 ppm hydrogen chloride with a boron content of 5.7 ppm. Under agitation at room temperature 2 ml hexachlorodisiloxane were injected through the pierced stopper with the aid of a syringe below the level of liquid in the chlorosilane mixture over a period of 3 to 4 seconds. The injected hexachlorodisiloxane was immediately dispersed in -the chlorosilanes without clouding.
The mixture was agita-ted for 30 min without under going heating and subsequently the chlorosilanes were frac-tionally distilled. In -the reamining residue of approx.
500 g SiCl~, approxO 57 ppm boron were detected.
Approx. 2.7 kg trichlorosilane and ca. 1.6 kg tetrachlorosilane in addition to approx. 200 g of intermediate fraction (mix-ture of HSiC13 and SiCl~) were produced by distilling. A silicon rod was produced Erom the trichloro-in a known manner. After the seventh zone-melting in a vacuum it has a resistance of 12200 Q cmO
Example 2 5000 g of the trichlorosilane raw product named therein were introduced into the apparatus described in Example 1. 2 ml of a suspension of 0.4 g silico-formic anhydride in tetrachlorosilane were added under agitation -to this product. This- suspension dissolved slowly in the chloro silane mixture at normal temperature. A fine dispersion was obtained which became clear within a short period.
The mixture was then agitated for 1 hour without being heated and then, similarly to Example 1, was distilled.
Ca. 2.8 kg of trichlorosilane and ca. 1.5 kg of tetrachlorosilane in addition to approx. 200 g of intermediate fraction (~SiC13/SiC14 mixture) are produced. 54 ppm of boron were analysed in the residue of ca. 500 g SiC14. (No boron could be detected by spectrometer either in the trichlorosilane distillate or in the tetrachlorosilane distillate in the 200 g of intermediate fraction).
Example 3 Example 2 ls followed except that 0.5 g pyroyenic silicic acid is added to the chlorosilane mixture. The silicic acid was dispersed over a short period of time through the entire reaction container. A slight cloudiness of SiO2 in the chlorosilanes remained throughout the process. The working up was along the lines of Example 2.
A mlnute precipitate of SiO2 with a boron content of 3860 ppm remained in the distillation residue. Another 50 ppm approx. of boron were measured in the liquid dis-tll-lation residue. No boron could be detected in any of the distillates using spectroanalytic methods.
Example 4 5000 g of trichlorosilane were introduced into the multiple-neck flask referred to ln Example 1. The trichloro-silane had a boron content of 26.4 ppm. While effecting agitation at room temperature, 1 ml of 20~ dilu-te hydrochloric acid is injected below the liquid level of the trichlorosilane through the pierced stopper with the aid of a syringe with a long needle over a period of 2 to 3 seconds. The injected hydrochloric acid disappeared without any externally visible signs of a reaction and the product in the Elask did not become cloudy but remained cleat. The t~ichlorosilane was then agitated for a further lO min approx. without being heated.
The trichlorosllane treated in this manner was then drawn off through the bottom valve into a distillation column with ca. 35 plates and all the material distilled over in a fraction (4650 g yield) at 31C. The still contained only the hold-up of the column of approx. 250 ml with a boron content of >300 ppm.
The distillate was exarnined at regular intervals both colorimetrically and spectroscopically for boron. The limit of scope of this examination was ascertained in the blank test to be 0.1 ppb and/or <50 nanogram. No boron was found in the distillate during or after distillation. Silicon rods were manufactured from the trichlorosilane obtained in a manner known in itself and purified still further by zone-melting. The measurement of the resistance of the Si-rods obtained gave values between 9200 and 10,700 so cm.
E mple 5 As in Example l, 0.~ ml of concentrated aqueous hydxochloric acid was injected into 5000 g of a typical trichlorosilane crude product, consisting of 92.6% trichloro-silane, 7.~ tetrachlorosilane and ca. 400 ppm dichloro-silane with a boron content of 1.92 ppm, whereby the hydro-chloric acid immediately dissolved without clouding. The mixture was agitated for 30 min without being heated and then the entire trichlorosilane (ca. 4550 g) was distilled over. After distillation the remaining content of the still, ca. 300 ml, consisting mainly of tetrachlorosilane, had a boron content of 518 ppm.
Blank values for boron were found in the trichloro-silane distillate regularly by colorimetric and spectro-_g_ . .
~8~
scopic analysis. the measurement ox resistance of Si-rods manufactured from thls gave values of be-tween 9700 and 11,800 Q cm.
Example 6 300 g of technical trichlorosilane, in which is dissolved 632 ppm of hydrogen chloride is fed at ca. 20C in liquid aggregate state with a flow velocity of 2.2 litre/h through a glass gas chromatographie column (diameter 50 mm, filling height 1150 mm?, filled with silica gel (pore diameter ca. 10 mm, grain size ca. 50-200 em, ASTM ca. 60-250 mesh)O
The trichlorosilane used also contained 12.4 ppm boron. After it had passed through no further traces of boron were detectable.
Polycrystalline silicon rods manufactured from trichlorosilane purified in this way gave resistance values of >10,000 Q cm.
Examples 7-14 Analogous to Example 6 a further eight 300 kg batches of boron-containing trichlorosilane with hydrogen chloride dissolved therein were fed in after each other through the same chromatographic SiO2 column already used in Example 6.
Likewise this was performed in the liquid phase:
HCl content boron content Flow velocity Example ppm ppm litre/h 7 2021 22.1 2.2 8 478 8.4 2.2 9 729 4.8 2.2 1402 11.2 2.2 11 68~ 32.5 2.2 12 275 8.2 2.2 13 1063 10.6 2.2 14 542 5.7 2.2 . .
2~
The pure trichlorosilane obtained was examined in 30 kg batches and reduced to silicon rods. In none of the 30 kg tests was boron detectable by colorimetric anal~vsis.
All silicon rods gave resistance values of >lO,OOOQcm.
The purification power of the columns used in Example 6 to Example 14 was undiminished at the comple-tion o Example 14.
Comparat ve Example In comparison to Example 6 a technical trichlorosilane with a boron content of 7.2 ppm, yet free from hydrogen chloride was used in exactly the same process. After every 120 minutes the trichlorosilane flowing out of the column was examined by colorimetric analysis for its boron content:
time trichlorosilane min discharged boron value kg 120 3.2 boron-free 240 6.5 boron-free 360 9.8 14 ppb 480 13.0 0.4 ppm 600 16.2 2.5 ppm 720 19.5 6.8 ppm Without hydrogen chloride, the column will cease to operate faultlessly after 6 hours, and will be exhausted after 10-12 hours Example 15 5 kg of tetrachlorosilane were introduced into a 4-litreagitator (mul-tiple-neck) flask made of laboratory-apparatus glass and equipped with a nitroqen cover and pierceable cap The tetrachlorosilane contained the following impurities:
copper 22 ppb nickel 48 ppb cobalt 39 ppb iron 22~ ppb manganese18 ppb chromium 28 ppb vanadium 16 ppb.
4 ml of a 25% solution of hydrogen~chloride in hexachloro~
disiloxane were injected at about 20C, during stirring, with the aid of a hypodermic syringe having a long needle, through the pierceable cap, into the liquid phase. After a three-hour reaction period at about 20C, the charge was transferred to the boiler of a distilling column. A:Eter 10 minutes of degasification, it was distilled out by reflux boiling with a reflux ratio of 1.
This produced about 5 kg of tetrachlorosilane of the following purity:
copper 6 ppb nickel 9 ppb cobalt 3 ppb iron 3 ppb manganese 2 ppb chromium 3 pPb vanadium< 4 ppb~
Example 16 As in Example 15, 5 kg of tetrachlorosilane, having a trichlorosilane content of 32 ppm and containing about the same amount of metal impurities as the material wsed in the preceding example, were treated with 5 ml of 25% aqueous hydrochloric acid. This produce a tetrachlorosilane containing <10 ppb of trichlorosilane and ~10 ppb of any metal impurity.
.
disiloxane were injected at about 20C, during stirring, with the aid of a hypodermic syringe having a long needle, through the pierceable cap, into the liquid phase. After a three-hour reaction period at about 20C, the charge was transferred to the boiler of a distilling column. A:Eter 10 minutes of degasification, it was distilled out by reflux boiling with a reflux ratio of 1.
This produced about 5 kg of tetrachlorosilane of the following purity:
copper 6 ppb nickel 9 ppb cobalt 3 ppb iron 3 ppb manganese 2 ppb chromium 3 pPb vanadium< 4 ppb~
Example 16 As in Example 15, 5 kg of tetrachlorosilane, having a trichlorosilane content of 32 ppm and containing about the same amount of metal impurities as the material wsed in the preceding example, were treated with 5 ml of 25% aqueous hydrochloric acid. This produce a tetrachlorosilane containing <10 ppb of trichlorosilane and ~10 ppb of any metal impurity.
.
Claims (23)
1. A method for removing from a chlorosilane, boron, metal compounds, hydrogensilanes and mixtures thereof contained in the chlorosilane as impurities, characterized in that, at a temperature of from 0°C to 30°C, the chlorosilane is brought, in the liquid phase, into intimate contact with compound soluble in said chlorosilane and containing one or more Si - O - Si groups, in amounts of 0.005 to 0.1% by weight relative to the chlorosilane, in the presence of 0.005 to 0.1% by weight, relative to the chlorosilane, of hydrogen-halide, the chlorosilane thus purified being then separated from the resulting less volatile compound or com-pounds, said less-volatile compound or compounds being soluble in the chlorosilane, the separation of the less-volatile compound or compounds being effected by distillation.
2. A method according to claim 1, characterized in that tetrachlorodisiloxane and/or higher homologues thereof are used as a compound containing said Si - O - Si groups.
3. A method according to claim 1 or claim 2, characterized in that said hydrogen-halide is hydrochloric acid.
4. A method according to claim 1 or claim 2, characterized in that said hydrogen-halide is hydrochloric acid and in that said compound containing said Si - O - Si groups is produced in situ by contacting the liquid chloro-silane with hydrochloric acid having a concentration above 1.050 g/l.
5. A method for removing from a chlorosilane, boron, metal compounds, hydrogensilanes and mixtures thereof contained in the chlorosilane as impurities, characterized in that, at a temperature of from 0°C to 30°C, the chlorosilane is brought, in the liquid phase, into intimate contact with a compound soluble in said chlorosilane and containing one or more Si - O - Si bonds, in amounts equal to or greater than 0.005% by weight relative to the chlorosilane, in the presence of 0.005 to 0.1% by weight, relative to the chlorosilane, of hydrogen-halide, the chlorosilane thus purified being then separated from the resulting less-volatile compound or com-pounds, said less-volatile compound or compounds being soluble in the chlorosilane, the separation of the less-volatile compound or compounds being effected by distillation.
6. A method according to claim 5, characterized in that use is made of tetrachlorodisiloxane and/or higher homologues thereof as a compound containing said Si - O - Si groups.
7. A method according to claim 5 or claim 6, characterized in that said hydrogen-halide is hydrochloric acid.
8. A method according to claim 5 or claim 6, characterized in that said hydrogen-halide is hydrochloric acid and in that said compound containing said Si - O - Si groups is produced in situ by contacting the liquid chloro-silane with hydrochloric acid having a concentration above 1.050g/l.
9. A method for removing from a chlorosilane, boron, metal compounds, hydrogensilanes and mixtures thereof contained in the chlorosilane as impurities, characterized in that, at a temperature of from 0°C to 30°C, the chlorosilane is brought, in the liquid phase, into intimate contact with SiO2 in a chromatographic column, in amounts equal to or greater than 0.005% by weight relative to the chlorosilane, in the presence of 0.005 to 0.1% by weight, relative to the chlorosilane, of hydrogen-halide, the chlorosilane thus purified being then separated from the SiO2.
10. A method according to claim 9, characterized in that finely divided SiO2 is used.
11. A method for removing from a chlorosilane, boron, metal compounds, hydrogensilanes and mixtures thereof contained in the chlorosilane as impurities, characterized in that, at a temperature of from 0°C to 30°C, the chlorosilane is brought, in the liquid phase, into intimate contact with SiO2, in amounts equal to or greater than 0.005% by weight relative to the chlorosilane, in the presence of 0.005 to 0.1% by weight, relative to the chlorosilane, of hydrogen-halide, the chlorosilane thus purified being then separated from the SiO2.
12. A method according to claim 11, characterized in that finely divided SiO2 is used.
13. A method for removing from a chlorosilane, boron, heavy metal compounds, hydrogensilanes and mixtures thereof contained in the chlorosilane as impurities, charac-terized in that the chlorosilane is brought, in liquid phase, into intimate contact with SiO2 in the presence of 0.005 to 0.1% by weight, relative to the chlorosilane, of hydrogen-halide, the chlorosilane thus purified being then separated from the SiO2.
14. A method according to claim 13, characterized in that the treatment with SiO2 is carried out at a tempera-ture of from 0°C to 30°C.
15. A method according to claim 13, characterized in that finely divided SiO2 is used.
16. A method for removing from a chlorosilane, boron, heavy metal compounds, hydrogensilanes and mixtures thereof contained in the chlorosilane as impurities, charac-terized in that the chlorosilane is brought, in liquid phase, into intimate contact with a compound soluble in said chloro-sialne and containing one or more Si - O - Si groups in the presence of 0.005 to 0.1% by weight, relative to the chloro-silane, of hydrogen halide, the chlorosilane thus purified being then separated from the resulting less-volatile com-pound or compounds said less-volatile compound or compounds being soluble in the chlorosilane, the separation of the less-volatile compound or compounds being effected by distillation.
17. A method according to claim 16, characterized in that the treatment with said compound containing said Si - O - Si groups is carried out at a temperature of from 0°C to 30°C.
18. A method according to claim 16, characterized in that tetrachlorodisiloxane and/or higher homologues thereof are used as a compound which contains said Si - O - Si groups.
19. A method according to claim 16, characterized in that said compound containing said Si - O - Si group is used in quantities between 0.005 and 0.1% by weight, relative to the chlorosilane.
20. A method according to claim 18, characterized in that said compound containing said Si - O - Si group is used in quantities between 0.005 and 0.1% by weight, relative to the chlorosilane.
21. A method according to claim 16, characterized in that the compound containing said Si - O - Si groups is produced in situ by contacting the liquid chlorosilane with hydrochloric acid.
22. A method according to claim 21, characterized in that hydrochloric acid having a concentration above 1.050 g/l is used for said contacting.
23. A method for removing from a chlorosilane, boron, metal compounds, hydrogensilanes and mixtures thereof contained in the chlorosilane as impurities, characterized in that the chlorosilane is brought, in the liquid phase, (i) into intimate contact with a compound soluble in said chlorosilane and containing one or more Si - O - Si groups, in the presence of 0.005 to 0.1% by weight relative to the chlorosilane of hydrogen-halide, the chlorosilane thus purified being then separated from the resulting less-volatile compound or compounds, said less-volatile compound or compounds being soluble in the chlorosilane, the separation of the less volatile compound or compounds being effected by distillation, or (ii) into intimate contact with SiO2, in the presence of 0.005 to 0.1% by weight, relative to the chlorosilane, of hydrogen-halide, the chlorosilane thus purified being then separated from the SiO2.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3049044.9 | 1980-12-24 | ||
| DE3049044 | 1980-12-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1189286A true CA1189286A (en) | 1985-06-25 |
Family
ID=6120291
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000393042A Expired CA1189286A (en) | 1980-12-24 | 1981-12-23 | Process for purifying chlorosilanes |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0054650B1 (en) |
| JP (1) | JPS57135712A (en) |
| CA (1) | CA1189286A (en) |
| DE (1) | DE3173646D1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5026533A (en) * | 1987-04-04 | 1991-06-25 | Huls Troisdorf Ag | Method and apparatus for the preparation of dichlorosilane |
| CN102666381A (en) * | 2009-12-04 | 2012-09-12 | 斯帕恩特私人有限公司 | Method for producing halogenated polysilanes |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1207127A (en) * | 1982-09-29 | 1986-07-08 | Dow Corning Corporation | Purification of chlorosilanes |
| DE10030252A1 (en) | 2000-06-20 | 2002-01-03 | Degussa | Separation of metal chlorides from their suspensions in chlorosilanes |
| JP4780284B2 (en) * | 2005-06-21 | 2011-09-28 | 三菱マテリアル株式会社 | Purification method of silane trichloride |
| JP5429464B2 (en) * | 2009-07-16 | 2014-02-26 | 三菱マテリアル株式会社 | Purification method of silane trichloride |
| CN103241742B (en) * | 2013-05-13 | 2015-02-18 | 杨恺 | High-purity SiCl4 purification method |
| JP6095613B2 (en) * | 2014-07-10 | 2017-03-15 | 信越化学工業株式会社 | Purification method of chlorosilane |
| CN115594184B (en) * | 2022-10-31 | 2023-10-10 | 唐山三孚硅业股份有限公司 | Electronic grade silicon tetrachloride production system and method |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL130371C (en) * | 1958-12-16 | 1900-01-01 | ||
| DE1289834B (en) * | 1960-08-11 | 1969-02-27 | Haldor Frederik Axel Dipl Ing | Process for purifying an inorganic halide compound or a mixture of such halide compounds |
| DE1157206B (en) * | 1962-09-29 | 1963-11-14 | Dynamit Nobel Ag | Process for the separation of titanium tetrachloride from solutions in chlorosiloxanes |
| DE2546957C3 (en) * | 1975-10-20 | 1980-10-23 | Wacker-Chemitronic Gesellschaft Fuer Elektronik-Grundstoffe Mbh, 8263 Burghausen | Process for cleaning halosilanes |
| DD135613A1 (en) * | 1977-11-09 | 1979-05-16 | Erich Wolf | PROCESS FOR THE PREPARATION OF BORAROUS CHLOROSILANES |
| FR2496086B1 (en) * | 1980-12-16 | 1985-07-12 | Quartz & Silice | OPTICAL WAVEGUIDE WITH FLUORIC DOPED HEART |
-
1981
- 1981-10-15 DE DE8181108342T patent/DE3173646D1/en not_active Expired
- 1981-10-15 EP EP81108342A patent/EP0054650B1/en not_active Expired
- 1981-12-23 CA CA000393042A patent/CA1189286A/en not_active Expired
- 1981-12-24 JP JP56208223A patent/JPS57135712A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5026533A (en) * | 1987-04-04 | 1991-06-25 | Huls Troisdorf Ag | Method and apparatus for the preparation of dichlorosilane |
| CN102666381A (en) * | 2009-12-04 | 2012-09-12 | 斯帕恩特私人有限公司 | Method for producing halogenated polysilanes |
| EP2507174B1 (en) | 2009-12-04 | 2013-11-06 | Spawnt Private S.à.r.l. | Method for producing halogenated polysilanes |
| US9040009B2 (en) | 2009-12-04 | 2015-05-26 | Spawnt Private S.à.r.1. | Kinetically stable chlorinated polysilanes and production thereof |
| US9139702B2 (en) | 2009-12-04 | 2015-09-22 | Spawnt Private S.A.R.L. | Method for producing halogenated polysilanes |
| US9458294B2 (en) | 2009-12-04 | 2016-10-04 | Spawnt Private S.À.R.L. | Method for removing impurities from silicon |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0054650A1 (en) | 1982-06-30 |
| JPS57135712A (en) | 1982-08-21 |
| DE3173646D1 (en) | 1986-03-13 |
| EP0054650B1 (en) | 1986-01-29 |
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