A study on Al2O3 passivation in GaN MOS-HEMT by pulsed stress

This paper studies systematically the drain current collapse in AlGaN/GaN metal-oxide-semiconductor high electron mobility transistors (MOS-HEMTs) by applying pulsed stress to the device.Low-temperature layer of A1 2 O 3 ultrathin film used as both gate dielectric and surface passivation layer was deposited by atomic layer deposition (ALD).For HEMT,gate turn-on pulses induced large current collapse.However,for MOS-HEMT,no significant current collapse was found in the gate turn-on pulsing mode with different pulse widths,indicating the good passivation effect of ALD A1 2 O 3.A small increase in I d in the drain pulsing mode is due to the relieving of self-heating effect.The comparison of synchronously dynamic pulsed I d V ds characteristics of HEMT and MOS-HEMT further demonstrated the good passivation effect of ALD A1 2 O 3.