The investigation of AlGaN/GaN HEMT failure mechanisms under different temperature conditions

摘要

To explore degradation law and failure mechanisms of AlGaN/GaN HEMT under different temperature conditions, the step-temperature stress experiments are carried out. The results show that the drain-source current decreases with the aging time when the junction temperature range from 139°C to 200°C; while the drain-source current increases with the aging time when the junction temperature range from 200°C to 352°C. When the junction temperature is less than 200°C, the AlGaN ionized donor atoms cause the Schottky barrier height of the AlGaN/GaN HEMT device to rise; and when the junction temperature is higher than 200°C, the diffusion of impurities oxygen in surface causes the Schottky barrier height of the AlGaN/GaN HEMT device to fall. The barrier height can affect the threshold voltage which leads to the change of drain-source current. Therefore, the degradation of the drain-source current is caused by the change of the Schottky barrier height.