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 H3SiCH2SiH3 and HC(SiH3)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 HSiCl3 and HCCl3 in the presence of an amine (Benkeser reaction) and the direct synthesis from silicon and polychloromethanes proved most promising for large scale preparations. The CH2X2/KSiH3 metathesis is most useful on the laboratory scale. - The Grignard synthesis was employed for partly methylated homologues, like H3SiCH2SiH2CH3, H3SiCH2SiH(CH3)2, H3SiCH2Si(CH3)3, and related molecules. The magnesium reduction of CHBr3/SiCl4 and CHBr3/CH3SiCl3 mixtures serves best for the preparation of HC(SiCl3)3, which can be converted into HC(SiH3)3 using LiAlH4. Attempts to synthesize tetrasilylmethane via the same route, C(SiH3)4, led only to the formation of HC(SiH3)3.