Method for purifying halogenated oligosilanes

Abstract

1. The present invention relates to a method for the purification of halogenated oligosilanes as a pure compound or mixture of compounds each having at least one direct Si—Si bond, the substituents thereof being exclusively halogen or halogen and hydrogen, and the composition thereof being an atom ratio of substituent:silicon of at least 3:2, by the action of at least one purification agent on the halogenated oligosilane and isolation of the halogenated oligosilane with improved purity. 2.1. In the prior art, halogenated monosilanes such as HSiCl3 are purified by treatment with preferably polymeric organic compounds containing amino groups, and are separated out from these mixtures. This method cannot be used for halogenated oligosilanes because of the contained amino groups, since secondary reactions would lead to decomposition of the products. The new method should provide the desired products in high yield and purity without amino groups being used. 2.2. The purification of the halogenated oligosilanes is carried out in the presence of special purification agents, which convert contaminations such as, for example, FeCl2 into an insoluble and/or less volatile form. A separation of the products of completes the purification This method gives a high yield and avoids the problems associated with the prior art, such as, for example, long distillation times. 2.3. The method is suitable for the purification of, for example, Si2Cl6, Si3Cl8, Si4Cl10, and higher homologs. These find application, for example, in the deposition of silicon nitride layers in CVD processes.

Dependencies are inferred from the claim text.