Comparative Breakdown Study of Mesa- and Ion-Implantation-Isolated AlGaN/GaN High-Electron-Mobility Transistors on Si Substrate

This letter reports a comparison of AlGaN/GaN high-electron-mobility transistors (HEMTs) fabricated on the same wafer using mesa etch or ion implantation as the isolation technology. The devices fabricated with ion implantation show similar DC performance (i.e., current density and on-resistance) to the devices with mesa isolation but have a higher breakdown voltage for the same gate-to-drain distance. AlGaN/GaN HEMTs with a breakdown voltage of 1800 V and specific on-resistance of 1.9 mΩ cm 2 have been realized through ion implantation isolation. The planarity of the device structure and field termination profile are keys to explain this increase in the breakdown voltage.