A process for removal of impurities, in particular of dopants, from chlorosilanes which includes the following steps: (a) heating a deposition surface (3); (b) contacting the heated deposition surface (3) with at least one gaseous chlorosilane mixture, the gaseous chlorosilane mixture including at least one chlorosilane and at least one impurity, in particular at least one dopant; (c) at least partially removing the impurity, in particular the dopant, by forming polycrystalline silicon depositions on the deposition surface (3), the polycrystalline silicon depositions being enriched with the impurity, in particular with the dopant; (d) discharging the purified gaseous chlorosilane mixture; (e) contacting the heated deposition surface (3) with an etching gas to return the polycrystalline silicon depositions and the impurity, in particular the dopant, into the gas phase to form a gaseous etching gas mixture; and (f) discharging the gaseous etching gas mixture.

The invention relates to a method for increasing the purity of oligosilanes and/or oligosilane compounds, in which a first liquid substance mixture formed from at least 50% oligosilane compounds comprising inorganic oligosilanes and/or halogenated oligosilanes and/or organically substituted oligosilanes is provided, and the first liquid substance mixture is subjected to at least one purification sequence, wherein in a first step a) the liquid substance mixture is temperature adjusted to a temperature at which at least one fraction of the oligosilane compounds solidify, and in a second step b) at least one fraction of the liquid substance mixture is separated.

Provided is a method for purification of iodosilanes, such as diiodosilane. In this method, trace amounts of certain metal ion contaminants are removed, thus providing certain liquid compositions comprising the iodosilanes, which can be used advantageously in the deposition of silicon-containing films onto microelectronic device substrates.

In order to produce high-purity trichlorosilane by removing methyldichlorosilane from a mixture (S) containing methyldichlorosilane (CH.sub.3HSiCl.sub.2), tetrachlorosilane (SiCl.sub.4), and trichlorosilane (HSiCl.sub.3) in the method for producing trichlorosilane of the present invention, a procedure is employed in which chlorine atoms are redistributed between methyldichlorosilane and tetrachlorosilane through catalytic treatment for conversion into trichlorosilane and methyltrichlorosilane (CH.sub.3SiCl.sub.3). Methyldichlorosilane (boiling point: 41° C.) having a boiling point close to that of trichlorosilane (boiling point: 32° C.) to be purified is converted into methyltrichlorosilane (boiling point: 66° C.) having a higher boiling point through redistribution of chlorine atoms between methyldichlorosilane and tetrachlorosilane, achieving easy removal of impurities.

Trihalosilane refining device having a divided wall distillation column is disclosed. The trihalosilane refining device can be useful in obtaining high-purity trihalosilane from a feed containing a trihalosilane while consuming a small amount of energy.

The present invention relates to a process for preparing chlorinated oligosilanes, wherein chlorinated polysilane having an empirical formula of SiCl.sub.1.0-2.8 and/or a mixture comprising the chlorinated polysilane is reacted with elemental chlorine or a chlorine-containing mixture. Additionally claimed are chlorinated oligosilanes prepared by the process and the use thereof for production of semiconductors and/or hard coatings.

Chlorosilane-containing process streams are treated by vaporizing the process stream, contacting the vaporized process stream with an alkaline medium in a scrubber, the scrubbing liquid being maintained at a pH of 9-13 by introduction of alkaline medium, and feeding the scrubbing medium to a waste treatment plant containing at least one mixing tank in which the pH is adjusted to the range of 7-9 by addition of mineral acid, separating solids by means of a centrifuge, and isolating separated solids.

Separation of chlorosilane mixtures containing boron, arsenic, and/or phosphorus impurities is facilitated by a distillative separation using at least one divided column, with recycle streams to a first column being passed through an external absorbent for the impurities.

By incorporating an additional TCS and/or DCS redistribution reactor in the TCS recycle loop and/or DCS recycle loop, respectively, of a process and system for silane manufacture, efficiencies in the production of silane are realized. Further improvements in efficiencies may be realized by directing a portion of the product from a redistribution reactor into a distillation column, and specifically into the distillation column that formed the feedstock that went into the redistribution reactor.

[Problem] To provide a novel production method for pentachlorodisilane and to obtain pentachlorodisilane having a purity of 90 mass % or more by carrying out this production method.

[Solution] A production method provided with: a high-temperature reaction step in which a raw material gas containing vaporized tetrachlorosilane and hydrogen is reacted at a high temperature in order to obtain a reaction product gas containing trichlorosilane; a pentachlorodisilane generation step in which the reaction product gas obtained in the high-temperature reaction step is brought into contact with a cooling liquid obtained by circulative cooling of a condensate that is generated by cooling the reaction product gas, the reaction product gas is quickly cooled, and pentachlorodisilane is generated within the condensate; and a recovery step in which the generated pentachlorodisilane is recovered.