An Enhancement-Mode GaN p-FET With Improved Breakdown Voltage

In this letter, an enhancement-mode (E-mode) GaN p-channel field-effect transistors (p-FETs) with current density of −5. 6 mA/mm and I {₎₍}/I {₎₅₅} ratio of 10 6 was demonstrated on a p-GaN/AlN/AlGaN/GaN heterostructure on Si substrate. A decent ohmic contact resistivity of 9. 25 10^-5 {cm}^2 is achieved by capping the heterostructure with a 10-nm heavily Mg-doped p ++ -GaN epilayer. A two-step gate trench etching process, is implemented to overcome the decreased OFF-state blocking voltage associated with the surface p ++ -GaN layer. The proposed structure is compelling for monolithic integration of GaN-based logic and power devices.