Atomic layer deposition of phosphorus oxide films as solid sources for doping of semiconductor structures

摘要

Plasma-assisted atomic layer deposition (PALD) was carried out for growing thin phosphorus oxide films onto flat and high-aspect ratio substrates. The applicability of these films as dopant sources for shallow phosphorus doping using different rapid thermal annealing (RTP) methods, such as conventional RTP and flash lamp anneal (FLA), was investigated. The phosphorus oxide films were, as expected, highly unstable in ambient air and needed to be stabilized for further ex-situ investigation. Conformal growth of such films could be obtained on silicon trench structures up to ~ 15: 1 aspect ratio with pitch below 50 nm. Shallow phosphorus doping of silicon could be obtained using the respective oxide films as dopant sources.