A new AlGaN/GaN power HFET employing partial deep trench drain structure for high voltage application

A new AlGaN/GaN heterojuction field effect transistor (HFET) employing the partial deep trench drain structure for high voltage application has been proposed and verified successfully to achieve low leakage current and small Rdson. In order to reduce leakage current and on-resistance of HFET devices, we propose a partial deep trench on drain edge adjacent to access region for the first time, which contributes to reducing the surface electric field under the off-state. In addition, trenched area under drain Ohmic metal enhances Ohmic contact on the surface of AlGaN layer which reduces contact resistivity of drain Ohmic contact. The proposed deep trench drain successfully reduces Ohmic contact resistance under the on-state and leakage current under the off-state at the same time.