Synthesewege zu einfachen Di- und Trisilylmethanen: Potentielle Ausgangsstoffe für die CVD-Abscheidung von amorphem Silicium a-SiC: H / Synthetic Pathways to Simple Di- and Trisilylmethanes: Potential Starting Materials for the CVD Deposition of Amorphous Silicon a-SiC :H

Abstract

Abstract Methods for the preparation of simple silaalkanes with a high content of silicon and hydrogen have been explored. Target molecules, like H 3 SiCH 2 SiH 3 and HC(SiH 3 ) 3 , may serve as precursor molecules for the production of photovoltaic elements through thermal or discharge (plasma) CVD processes. Among a variety of synthetic pathways, the reactions between HSiCl 3 and HCCl 3 in the presence of an amine (Benkeser reaction) and the direct synthesis from silicon and polychloromethanes proved most promising for large scale preparations. The CH 2 X 2 /KSiH 3 metathesis is most useful on the laboratory scale. - The Grignard synthesis was employed for partly methylated homologues, like H 3 SiCH 2 SiH 2 CH 3 , H 3 SiCH 2 SiH(CH 3 ) 2 , H 3 SiCH 2 Si(CH 3 ) 3 , and related molecules. The magnesium reduction of CHBr 3 /SiCl 4 and CHBr 3 /CH 3 SiCl 3 mixtures serves best for the preparation of HC(SiCl 3 ) 3 , which can be converted into HC(SiH 3 ) 3 using LiAlH 4 . Attempts to synthesize tetrasilylmethane via the same route, C(SiH 3 ) 4 , led only to the formation of HC(SiH 3 ) 3 .