A closed-form analytical forward transit time model considering specific models for bandgap-narrowing effects and concentration-dependent diffusion coefficients for BJT devices operating at 77 K

摘要

The authors report a closed-form analytical low-temperature forward transit time model considering bandgap-narrowing effects and concentration-dependent diffusion coefficients based on the entire shape of the emitter and base doping profiles for bipolar junction transistor (BJT) devices operating at 77 K. As verified by the PISCES simulation results, the new closed-form analytical model provides a better low-temperature forward transit time model compared to the model in which bandgap-narrowing effects and concentration-dependent diffusion coefficients are not considered.