Numerical Modeling of Oxide and Interface Charge Buildup in Field Oxide Transistors During Irradiation and Annealing

The response of n-channel field-oxide field-effect transistors (FOXFETs) exposed to ionizing radiation and annealing is reproduced using a physics-based numerical model that includes the microscopic processes leading to hole capture/ neutralization and generation of interface traps. The results show that a distribution for the proton emission rate has to be considered to reproduce the threshold voltage evolution with dose, and density of interface traps trends at both short and long post-irradiation annealing times if direct release is considered as the mechanism responsible for proton production. This result may suggest a failure of the usual simple drift-diffusion model for proton transport across SiO2 in total dose models, or a limitation of our model based on some processes that were neglected in the first approach, such as hydrogen cracking as a secondary mechanism for proton production.