Low Specific On-Resistance AlGaN/GaN HEMT on Sapphire Substrate

On-resistance of AlGaN/GaN HEMTs with MIS and MES gate structures has been investigated. In the case of the MES gate structure, the HEMT with specific on-resistance lower than 0.1 mOmegacm 2 was obtained by shortening the drain-source length to 2.2 mum. The maximum transconductance g m,max and the off-state breakdown voltage were 220 mS/mm and 35 V, respectively. Tradeoff characteristic of the specific on-resistance and the breakdown voltage of the AlGaN/GaN MES-gate HEMT exceeded theoretical limit of Si-based devices. In the case of the MIS-gate HEMTs, by shortening the source-drain length to 1.8 mum, the specific on-resistance lower than 0.17 mOmegacm 2 and the maximum drain current of 920 mA/mm were obtained