Heat Effect in a Vertical Grounded-Base NPN Bipolar Junction Transistor under ESD Stress

An analysis of the heat effect involved in a vertical grounded-base n-p-n (VGBNPN) bipolar junction transistor under electrostatic discharge (ESD) stress is first carried out by a two-dimensional Semiconductor Device-Circuit Simulator (SDCS). The heat flow equation is employed to calculate the temperature raise which diminishes the generating rate and other parameters of carriers in the BJT, and causes the voltage clamping function of the VGBNPN to weaken. When temperature reaches the limit that the BJT material can bear, the transistor burns and the protection fails.