3.2 kV AlGaN/GaN MIS-HEMTs employing RF sputtered Ga2O3 films

AlGaN/GaN metal insulator semiconductor high electron mobility transistors (MIS-HEMTs) employing rf sputtered Ga₂O₃ have been proposed and fabricated. A very high breakdown voltage exceeding 3200 V and a low drain leakage current of 230 nA/mm at gate-drain distance (L_GD) of 40 μm was achieved without any sacrificing DC output characteristics while those of the unpassivated HEMT were 350 V and 134 μA/mm. The breakdown voltage of the Ga₂O₃ passivated HEMT was increased with increase of L_GD because the injected electrons into the deep traps in Ga₂O₃ effectively extended the depletion region between the gate and the drain. And the injected electrons into deep traps have high activation energy for de-trapping so that the reverse blocking characteristics of the Ga₂O₃ passivated HEMT were considerable improved.