Influence of thermal annealing on AlGaN/GaN HEMT by fluorine plasma treatment

The influence of thermal annealing on four kinds of AlGaN/GaN high electron mobility transistors (HEMTs) with different fluorine plasma treatment power were compared and analyzed in detail. A thin fluorinated layer between the Schottky metal and the AlGaN barrier layer which produced with fluorine plasma treatment was conformed by the comparison of Schottky reverse gate leakage current before annealing and after annealing. The maximum saturation current and the peak transconductance of HEMTs decreased with the fluorine plasma treatment power increasing before annealing, and they were recovered partially after annealing. The hysteresis of double sweep curves by fluorine plasma treatment was enlarged. F− ions could introduce the acceptor state in the barrier layer, and high temperature could eliminate some trap states introduced by fluorine plasma treatment.