''Universal'' dependence of avalanche breakdown on bandstructure: Choosing materials for high-power devices

A new simple phenomenological relation between the breakdown voltage V-b and the bandstructure in semiconductor junctions is presented. For narrow-gap semiconductors, V-b scales with the minimum energy gap (E(g)) as has been previously reported. However, for wide-gap materials including GaAs, InP, etc., V-b is linearly dependent on [E], a Brillouin-zone-averaged energy gap. Values of [E] are determined from accurate quasi-particle bandstructures for 25 tetrahedral semiconductors. We discuss the origin of this relation and the role of the ionisation probability and electron-phonon scattering rate. The relation can be used to predict the breakdown voltage in semiconductors and semiconductor alloys.