High breakdown voltage AlGaN/GaN HEMTs employing fluoride plasma treatment

Abstract

We proposed channel-modulated AlGaN/GaN high electron mobility transistors (HEMTs) employing fluoride plasma treatment and carried out a detailed numerical simulation of device operation using ISE TCAD software. A reduction of peak electric field is required for achieving the high breakdown voltage of AlGaN/GaN HEMTs. The proposed channel-modulated AlGaN/GaN HEMTs created the fluoride plasma-treated region between the gate and the drain. The fluoride plasma-treated region modulated the two-dimensional electron gas (2-DEG) channel concentration, and effectively reduced the peak electric field without any field plates. The reduction of peak electric field in the gate-to-drain region caused the breakdown voltage to increase by 206%. The dc characteristics of channel-modulated AlGaN/GaN HEMTs remained practically the same as those of the conventional AlGaN/GaN HEMTs. The breakdown voltage could be increased without a significant degradation of dc characteristics due to the SiO2 passivation layer. The deposition of the SiO2 passivation layer combined with fluoride plasma treatment is a powerful process for channel-modulated AlGaN/GaN HEMTs.