Investigation of Electrical Property and Reliability in AlGaN/GaN MIS-HEMTs Fabricated by Using N₂/O₂ Composite Plasma Treatment

Metal–insulator–semiconductor-high electron mobility transistors (MIS-HEMTs) devices using recessed gate technology typically exhibit higher threshold voltage (V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</inf>) and are commonly employed in the fabrication of E-mode devices. A stable and reliable gate scheme is crucial for the development of enhancement-mode (E-mode) AlGaN/GaN MIS-HEMTs. This study reports a plasma etching approach using a nitrogen and oxygen composite plasma to repair and passivate the gate region. The fabricated devices demonstrate a high V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</inf> of 3.4 V and a gate breakdown voltage of 26 V. Furthermore, the device reliability is significantly improved compared to untreated device.