The effects of atomic-layer-deposited (ALD) Al2O3 passivation layer on AlGaN/GaN HEMTs on SiC were studied. Improved pulsed I-V characteristics and a relatively small decrease in the unity gain cutoff frequency (fT) and the maximum frequency of oscillation (f max) were observed in the devices passivated using a 45nm-thick ALD Al2O3 layer. For 0.12m gatelength devices, fT (fmax) decreased to 92GHz (115GHz) from 120GHz (140GHz), while for 0.25m devices, fT (fmax) decreased to 58GHz (120GHz) from 65GHz (137GHz). At a drain bias of 15V, an output power of 3W/mm with an associated gain of 5.0dB and PAE of 33 were obtained for the 0.25m gatelength devices.
ASJC Scopus subject areas
- Electrical and Electronic Engineering