Abstract
The power bipolar junction transistor (PBJT) is studied. The main interest is concentrated on the charge in the collector layer, which dominates the characteristics of the device. Based on the partial differential equations of semiconductor physics, ordinary differential equations for a one-dimensional model are derived for a PBJT with fine cell structure. The equations consider recombination, charging, and discharging processes in the collector layer. A network model for the PBJT is derived by adding these equations to the standard model. The model is implemented in IG-SPICE. The static behavior, like quasi-saturation, and the dynamic behavior, including turn off under a strong drive condition, can be simulated and analyzed. The simulation results correlate well with the measurement.