Low-Temperature Deposition of Silicon Dioxide and Silicon Nitride for Dual Spacer Application

Advanced sub 65 nm spacer applications require high quality conformal silicon dioxide and silicon nitride deposition processes at low thermal budgets. In this paper, we report on a study where these films were deposited using a novel Si precursor material that enables high deposition rates at temperatures typically around 250degC using a production-proven single wafer chemical vapor deposition (CVD) system (Planar 300trade) from Aviza Technology. Films are deposited with excellent non-uniformities, step coverage over challenging device structures and low particle counts. The reported silicon dioxide process is a purely thermal CVD process, whereas the silicon nitride process uses an RF plasma to initiate ammonia reactivity. The use of a single platform and single C- and Cl-free Si precursor enables sequential processing of C- and CI- free SiO₂ and SiN dual spacer layers at processing temperatures (< 400degC) compatible with advanced devices.