Self-heating effects in basic semiconductor structures

Investigates the effects of self-heating on the high current I -V characteristics of semiconductor structures using a fully coupled electrothermal device simulator. It is shown that the breakdown in both resistors and diodes is caused by conductivity modulation due to minority carrier generation. In isothermal simulations with T=300 K, avalanche generation is the source of minority carriers. In simulations with self-heating, both avalanche and thermal generation of minority carriers can contribute to the breakdown mechanism. The voltage and current at breakdown are dependent on the structure of the device and the doping concentration in the region with lower doping. For all structures, except highly doped resistors with poor heating sinking at the contacts, the temperature at thermal breakdown ranged from 1.25T_i to 3T_i , where T_i is the temperature at which the semiconductor goes intrinsic. Hence, it is found that T=T_i is not a general condition for thermal (or second) breakdown. From these studies, an improved condition for thermal breakdown is proposed