HIGH CURRENT DENSITY/HIGH VOLTAGE AlGaN/GaN HFETs ON SAPPHIRE

AlGaN/GaN heterojunction field effect transistors (HFETs) on sapphire substrates for power-switching applications have been fabricated. Design parameters such as source-gate spacing (L_sg), gate length (L_g), and gate width (W_g) have been varied to check their effects on the device performances. For a gate-drain spacing (L_gd) of 10μm, a specific on-resistance (AR_on) of 1.35mΩcm² and off-state breakdown voltage (BV) of 770V was achieved, which is close to the 4-H SiC theoretical limit.