The sensitivity of 100Â nm RADFETs with zero gate bias up to dose of 230Â Gy(Si)

The RADFETs (pMOS dosimeters) were irradiated by ionizing radiation from 60Co gamma-ray source to dose of 230 Gy(Si) without gate bias, and their reproducibility and sensitivity to radiation were investigated. The completely automatic system containing switching matrix have been used, enabling very reliable measurements of RADFET electrical characteristics. Two sample types from each RADFET chip, with the same gate oxide thickness, but different geometry (channel width and length), were investigated. The samples have shown good reproducibility of the threshold voltage shift during irradiation, i.e., the radiation sensitivity was similar for all samples. Using MG and CP techniques, it has been shown that the slow switching (border) trap density is negligible, but the fixed trap density saturates and the fast switching trap density is linear.