Conversion model of enhanced low-dose-rate sensitivity for bipolar ICs

A physical model is proposed for enhanced low-dose-rate sensitivity (ELDRS) in bipolar junction transistors. It is based on the conception of a shallow and a deep set of radiation-induced oxide traps that are converted into interface traps under irradiation at high or low dose rates, respectively. Excess base current is calculated by introducing an exponential or a power-law representation of the impulse response used in a convolution integral. The former representation makes it possible to define time constants of conversion at high or low dose rates, respectively. Values of fitting model parameters are determined that lead to close agreement with previously reported experimental results.