Cause and Effects of OFF-State Degradation in Hydrogen-Terminated Diamond MESFETs

This article reports the first comprehensive analysis of the reliability of hydrogen-terminated diamond metal semiconductor field-effect transistors (MESFETs) submitted to OFF-state stress. We demonstrate that stress induces an increase in ON-resistance and a shift in the threshold voltage, along with a decrease in the transconductance peak value. These effects are ascribed to the generation of defects at the diamond surface and/or in the upper semiconductor layers. The defects are generated both in the access regions and under the gate, and their activation energy is 0.30 eV.