Enhanced Total Ionizing Dose Susceptibility in Narrow Channel Devices

Total ionizing dose effects of different transistor sizes in a 0.18 μm technology are studied by 60 Co γ-ray irradiation. Significant threshold voltage shift is observed for the narrow channel devices, which is called the radiation induced narrow channel effect (RINCE). A charge sharing model is introduced to understand the phenomenon. The devices' characteristic degradations after irradiation, such as threshold voltage shift, increase in on-state current under different drain biases and substrate biases, are discussed in detail. Radiation induced oxide trapped charge at the edges of shallow trench isolation plays an important role in the RINCE. Narrow channel devices are susceptible to the total ionizing dose effect.