Avalanche breakdown of gallium arsenidep-njunctions†

Abstract

The ionization coefficient of carriers in gallium arscnide has been measured over the field range (2.5-5) × 10⁵ v cm^-1. The ionization coefficient, which has been previously shown equal for holes and electrons, was found to exhibit a field dependence given by α=α_∞ exp {—(b/8)²} where α_∞= 2.0×10⁵cm⁻¹ and b=5.5× 10⁵ v cm⁻¹. This is in fairly good agreement with recently reported data, but indicates a higher ionization coefficient in the lower field range. Consequently, the predicted breakdown voltages are slightly lower than those previously calculated, but in better agreement with experimental values. The difficulty in fitting the ionization coefficient with present theory is believed to be duo to the details of the band structure which are neglected in present theories.