A transistor model for numerical computation of forward-bias second-breakdown boundary

A two-dimensional bipolar power transistor model for numerical computation of the forward-bias, second-breakdown boundary is proposed. The model takes into account high-current-density effects such as the base widening (Kirk´s) effect and avalanche injection. The numerically determined forward-bias safe operating area is in good agreement with the experimentally obtained area, especially at high collector currents and lower collector voltages. The model is also used to analyze the dynamics of the forward-bias second breakdown. The model is verified experimentally, and is suitable for a parametric study of forward-bias second breakdown.