Impacts of residual chlorine in CVD-TiN gate electrode on the gate oxide reliability

摘要

Impact of CVD-TiN gate process on gate oxide integrity has been studied. Leakage characteristic and reliability of the gate oxide were drastically degraded by 1000°C anneal in thick oxide as compared to that of the thin oxide. By XPS and TDS analyses, the oxide degradation is confirmed to be due to the formation of the weak-spot induced by out-diffusion of residual Cl from the TiN gate electrode into the gate oxide. Out-diffused Cl reacts with defects in the oxide during the high temperature anneal and forms trap-site. The weak-spot which acts as leakage path seems to be the local spot which has larger amount of the Cl-related trap-site.