Energy Dependent Electron and Hole Impact Ionization in Si Bipolar Transistors

This paper describes a self-consistent procedure to extract energy dependent electron (/spl alpha/) and hole (/spl beta/) ionization coefficients directly from electrical measurements of multiplication factors (M/sub n/ and M/sub p/, respectively) carried out on a single reversed junction in a bipolar device. The extracted /spl alpha/ and /spl beta/ coefficients are used to accurately calculate breakdown voltages in a variety of bipolar devices. Results point out the role of holes and of non-local hole heating on the avalanche characteristics of modern bipolar devices.