Layout-Related Stress Effects on Radiation-Induced Leakage Current

The effects of shallow-trench-isolation-induced mechanical stress on radiation-induced off-state leakage current are reported in 90-nm NMOS devices. The radiation-induced leakage current increases with increasing active device-to-isolation spacing. The leakage current also depends on channel width; narrow devices exhibit less leakage before irradiation, but more after irradiation. These geometrical factors affect the mechanical stress in the device, which impact the dopant diffusion and activation and the charge trapping in the STI oxide. The combined effects of these layout-related phenomena affect the sensitivity to radiation-induced charge.