Effect of irradiation temperature on radiation damage in electron-irradiated MOS FETs

Results are presented of a study of radiation damage by high-temperature electron irradiation in submicron MOS FETs with standard thermal oxide and nitrogen annealed gate oxide as gate dielectric material. n-Channel MOS FETs were irradiated by 2-MeV electrons for the fluence of 1 × 1015 e/cm2 at 30, 100 and 200 °C. The drain leakage current in the cut-off region of MOS FETs increased with irradiation and the increase at 30 °C irradiation was the largest. However, the degradation of maximum transconductance of the MOS FETs tended to increase with increasing irradiation temperature due to the scattering induced by the change in positive trapped charge density and interface state density.