Mobile ion gettering in passivated p+ polysilicon gates

Abstract

Mobile ion contamination in the deep-submicron regime was studied for boron, arsenic, and phosphorus-doped polysilicon gates. An effective gettering process is presented for the passivation of p+ polysilicon gates without boron penetration through thin gate oxide. The issue of mobile ion gettering with p+ polysilicon in deep-submicron CMOS technology is also studied. A channel-length-dependent mobile ion instability was observed for the first time. A gettering/passivation process using polysilicon gates (PSG/LTO) with proper activation anneals was found to be effective for p+ polysilicon gated devices without causing boron penetration through the gate oxide