Time-dependent carrier flow in a transistor structure under nonisothermal conditions

A time-dependent temperature-dependent two-dimensional model has been developed to illustrate the internal behavior of bipolar transistors. Electrothermal interactions within the device are calculated in an attempt to better understand thermal instability modes. Numerically computed results are presented showing the electrical and thermal effects in the transistor operating in the switching mode during turn-on along a resistive load line. Plots of current density, electrostatic potential, and temperature versus time illustrate the combined effects of electrical rise time, thermal delay time, electrothermal interaction, current crowding, current spreading, conductivity modulation, and base pushout in bipolar transistors.