6.5 V High Threshold Voltage AlGaN/GaN Power Metal-Insulator-Semiconductor High Electron Mobility Transistor Using Multilayer Fluorinated Gate Stack

In this letter, the approach of partial AlGaN recess and multiple layers of fluorinated Al 2 O 3 gate dielectric is utilized to achieve highest reported positive gate threshold voltage ( $V_{{{\textrm {TH}}}}$ ) without severe reduction on 2-D electron gas carrier mobility in AlGaN/GaN HEMTs. Guided by the design and verification through analytical model, proper fluorine ions incorporation is made through fabrication. The approach resulted in a high $V_{{{\textrm {TH}}}}$ of +6.5 V and competitive drain saturation current ( $I_{{{\textrm {DMAX}}}}$ ) of 340 mA/mm. Furthermore, low gate leakage current and high breakdown voltage of 1140 V were also demonstrated.