Challenges in the electrochemical synthesis of Si2Cl6 starting from tetrachlorosilane and trichlorosilane

Abstract

The strongly increasing demand for nano- and microelectronics calls for new and environmentally benign reaction pathways for the preparation of one of the most important substrates in the production of semiconductor materials: Si2Cl6. We present a comprehensive study of the opportunities and challenges for the selective electrochemical formation of higher halo-functionalized silanes to Si2Cl6 achieved by cyclic voltammetry measurements and electrochemical synthesis. Cathodic dehalo-dimerization reaction of SiCl4 and the approach to halogen exchange for better substrate reduction are envisioned. An anodic halide-free dimerization pathway by dehydrogenation of HSiCl3 is investigated, including Lewis acid activation of the Si−H bond. In addition, tertiary amine-driven, Benkeser-like in-situ formation of a SiCl3− anion was tested as well. The target molecule Si2Cl6 is strongly promoted to direct electro-conversions making the anodic and cathodic electrosynthesis very challenging.