Investigation of the pulsed-IV degradation mechanism of GaN-HEMT under high temperature storage tests

The purpose of this study is to investigate the physical mechanism of pulsed-IV degradation under high temperature storage tests. Using the measurements of the pulsed S-parameters immediately after the voltage stress was applied to the GaN-HEMT, we carried out the delay time analysis. As a result, we found that the so-called “virtual gate” region extended toward the drain electrode due to high temperature storage. From this result, we concluded that the electron tunnel injection probability at the gate edge increased and degraded the pulsed-IV characteristics.