LEAKAGE CURRENTS IN SOI MOSFETS

Total-dose response of both NMOS and PMOS FETs fabricated on SOI substrates was studied. Two types of back-channel leakage currents were identified. A back-channel leakage due to MOSFET action uses the substrate bias as the gate bias. The other component is due to soft reverse characteristics of the body-drain junction. The back-channel leakage due to MOSFET action varies with the substrate bias and varies with irradiation due to the threshold voltage shift. The soft reverse characteristics are a function of drain-body voltage and vary with substrate bias and irradiation. I-V characteristics and subthreshold currents of both front and back channels as a function of total dose were obtained.