Diamond-like carbon (DLC) liner with highly compressive stress formed on AlGaN/GaN MOS-HEMTs with in situ silane surface passivation for performance enhancement

In this work, a highly compressive DLC liner (~ 6 GPa) was applied on AlGaN/GaN MOS-HEMTs for the first time. The compressive stress induced by DLC liner effectively reduces the tensile stress in the AlGaN layer, thus reducing the 2-DEG density. Devices with DLC show 22 % and 19% increase in drive current and peak transconductance, respectively, at V_G = 2 V and V_D = 10 V. Threshold voltage reduction of ~ 1 V was also observed for devices with DLC liner, as compared to ones without DLC liner. Devices in this work were also integrated with in situ silane (SiH₄) passivation technology.