Impact of peald AlN interfacial passivation layer on thin barrier AlGaN/GaN HEMTs

Two passivation techniques were applied on AlGaN/GaN high electron-mobility transistors (HEMTs) with thin barrier thickness (12 nm). 5 nm AlN interfacial passivation layer was deposited by plasma enhanced atomic layer deposition (PEALD) before 50 nm SiN protection layer grown by plasma enhanced chemical vapor deposition (PECVD). Compared with traditional SiN passivation, the insertion of AlN could suppress current collapse more effectively, and showed better characteristics such as smaller subthreshold slope (SS), lower drain induced barrier lower (DIBL), higher drain current and larger transconductance. Moreover, the DC-pulse curves showed that the channel self-heating effects were obviously alleviated due to the good heat spreading performance of AlN layer.