Abstract
This letter reports on the demonstration of recessed-gate ultra-wide bandgap semiconductor Al0.6Ga0.4N MOSFET with Hf0.5Zr0.5O2 (HZO) ferroelectric charge storage dielectric structure. A positive threshold voltage (V-TH) of 3.550 V and maximum gate swing of 15 V is achieved due to the trapped electrons induced by remnant polarization of HZO in gate stack. The Al0.6Ga0.4N MOSFET exhibits a specific on-resistance (R-on,R-sp) of 17.8 m omega center dot cm(2). Moreover, an 840 V breakdown voltage (BV) is obtained with a gate-to-drain (L-gd) length of 2 mu m, indicating an average breakdown electric field (E-av) beyond 4 MV/cm. In addition to the high E-av, a high BV > 3 kV is also derived on a transistor with L-gd = 8 mu m, translating to a power figure-of-merit (P-FOM=BV2/R-on,R-sp) of 208 MW/cm(2). These high device performances indicate a great potential of Al-rich E-mode AlGaN MOSFET for future high-power applications.