A Phosphine Sub Atmospheric Delivery System (SADS) Applied to Low Pressure Chemical Vapor Deposition (LPCVD) of In-Situ Doped Polysilicon

摘要

Phosphine gas is widely used as the phosphorus source for the deposition of in-situ doped n-type polysilicon. Typically, high pressure bottled phosphine gas is used for this purpose with excellent results. However, the safe use of a pressurized gaseous phosphine source requires a remote gas cabinet in a suitable location, double walled stainless steel tubing, and multiple toxic gas sensing points. The cost of this infrastructure can be prohibitive for many research laboratories. As a safe means around this cost issue, we have successfully implemented a commercially available phosphine SADS as the dopant source for in situ doped polysilicon. SADS has been proven as a safer source and can be installed locally, inside the source cabinet attached to the LPCVD furnace stack meeting all semiconductor industry safety requirements [1]. Based on the enhanced safety and reduced infrastructure requirements, we implemented SADS in the CNST NanoFab LPCVD system.