Silane production from the dichlorosilane by-product of the Siemens process: a comparative study with the trichlorosilane route

Abstract

The DCS-based silane production process exhibits higher reaction efficiency and lower energy consumption compared to the conventional TCS route, while enabling seamless integration with the Siemens process for polysilicon production. Silane (SiH 4 ), a critical electronic specialty gas for semiconductor and renewable energy technologies, is conventionally produced via trichlorosilane (TCS) disproportionation. This study introduced an innovative route utilizing dichlorosilane (DCS), a by-product of the Siemens process, and comparative analysis was also conducted between the reactive distillation (RD) and fixed-bed reactor (FBR) approaches. Process simulations demonstrate that, given TCS as the feedstock and the same silane output, the RD approach reduces energy consumption to <25% of conventional FBR systems by overcoming thermodynamic equilibrium through continuous product removal. When employing the RD approach, the energy consumption using DCS as the feedstock can be reduced to approximately 35% or 22% of that when TCS is utilized, depending on whether the main by-product is silicon tetrachloride (STC) or TCS. This improvement stems from the superior thermodynamic and kinetic properties of DCS disproportionation. The optimal process configuration depends on whether the silane production process is integrated with the Siemens process or a grassroots facility.