Fluoride monolayer doping in GaN/AlGaN/GaN semiconductor

With the evolution of the modern world, the demand for broadband network systems has been gradually grabbing significant attention in the high-tech industry. To meet the future requirements of intelligent life, unmanned devices and vehicles, the standard of six-generation (6G) wireless system is developing to integrate superior functions of low-orbit satellites and 5G cellular communication systems. For 6G wireless technology, the wide bandgap and high-electron-mobility transistors of GaN/AlGaN/GaN (HEMTs) are emerging as excellent candidates due to their high-power-handling capabilities and ability to small-scale fabrication to obtain minor and affordable chip size. However, the conventional GaN/AlGaN/GaN HEMTs, such as depletion-mode transistors with a negative threshold voltage (Vth), can limit the device application and their stability against temperature. Therefore, it is crucial to convert the gate-controlled channel from depletion- to enhancement mode, which can be achieved by introducing fluorine atoms into the channel. Herein, this study presents a method that can accurately control threshold voltages of GaN/AlGaN/ GaN using monolayer doping with 1H,1H,2H,2H-Perfluorooctyltriethoxysilane (POTS), a fluoride-containing molecule. This technique can prevent lattice damage from conventional methods such as ion implantation or plasma. This can open more process possibilities for next-generation high mobility GaN/AlGaN/GaN FinFETS to serve future-related 6G communication and low-orbit satellite circuit development.