Nitrogen Enhanced Oxygen Precipitation in Czochralski Silicon Wafers Coated with Silicon Nitride Films

Abstract

Oxygen precipitation (OP) behaviors were investigated for Czochralski (Cz) silicon wafers, which were coated with silicon nitride (SiNx) films or not, subjected to two-step anneal of 800C/4 h+1000°C/16 h following rapid thermal processing (RTP) at different temperatures ranging from 1150 to 1250C for 50 s. It was found that OP in the Cz silicon wafers coated with SiNx films was stronger in each case. This was because that nitrogen atoms diffused into bulk of Cz silicon wafer from the surface coated SiNx film during the high temperature RTP. Furthermore, it was proved that the RTP lamp irradiation facilitated the in-diffusion of nitrogen atoms, which was most likely due to that the ultraviolet light enhanced the breakage of silicon-nitrogen bonds.