The physical mechanisms governing DC breakdown in GaAs MESFETs

The combined processes of tunneling and impact ionization are identified as the physical mechanisms governing breakdown in GaAs MESFETs under pinch-off bias conditions. It is proposed that electrons tunnel through the Schottky barrier and then are accelerated towards the drain contact causing impact ionization in the high field region about the drain-sided gate edge. A new, simple model to describe the quantum-mechanical tunneling of the Schottky barrier is presented. This model has been incorporated into the fully self-consistent, two-dimensional device simulator MINIMOS. First results show excellent qualitative agreement with experimental data.<>