Insights on the transient response of fully and partially depleted SOI technologies under heavy-ion and dose-rate irradiations

The sensitivity of SOI technologies to transient irradiations (both dose rate and heavy ions) is analyzed as a function of the technology architecture with experiments and simulations. Two main parameters are considered. First, the thickness of the silicon film, which determines the fully or partially depleted state of SOI devices. This parameter strongly influences the parasitic bipolar, which amplifies the radiation-generated charge. In particular, fully depleted devices show a low bipolar gain due to a high-impact ionization. Secondly, the doping profile in the drain region, which varies with process optimization. The trend is to use shallow junctions to reduce short-channel effects in partially depleted devices. Shallow-drain junctions in partially depleted devices contribute to increases in drain-region sensitivity. As a result, fully depleted architectures are more adapted to reduce the radiation sensitivity of future SOI technologies, because it both reduces the bipolar amplification and the sensitivity of the drain region.