Effects of $\hbox{N}_{2}$ Plasma Pretreatment on the SiN Passivation of AlGaN/GaN HEMT

The impact of in situ low-power $\hbox{N}_{2}$ plasma pretreatment, prior to silicon-nitride (SiN) deposition, was investigated in AlGaN/GaN high-electron mobility transistors (HEMTs). These studies reveal that the use of $\hbox{N}_{2}$ plasma in HEMT passivation reduces current-collapse and gate-lag effects. Such treatment is also beneficial to improve gate leakage, and from RF measurements, no degradation of $f_{\max}$ was observed. These beneficial effects of the $\hbox{N}_{2}$ plasma pretreatment seem to be due to a significant reduction in interface charge density, as shown in this letter using GaN MIS devices, where a decrease of 60% was observed.