BV > 3 kV/V TH = 3.5 V Normally-Off Al 0.6 Ga 0.4 N MOSFET With Recessed-Gate and Ferroelectric Gate Dielectric.

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 ($\text{V}_{\text {TH}}$) 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 ($\text{R}_{\text {on,sp}}$) of ${17.8} \text {m}~\Omega \cdot \text {cm}^{{2}}$. Moreover, an 840 V breakdown voltage (BV) is obtained with a gate-to-drain ($\text{L}_{\text {gd}}$) length of $2 ~\mu \text{m}$ , indicating an average breakdown electric field ($\text{E}_{\text {av}}$) beyond 4 MV/cm. In addition to the high $\text{E}_{\text {av}}$ , a high BV > 3 kV is also derived on a transistor with $\text {L}_{\text {gd}} = {8}\,\,\mu \text {m}$ , translating to a power figure-of-merit (P-FOM=BV2/ $\text{R}_{\text {on,sp}}$) of 208 MW/cm2. These high device performances indicate a great potential of Al-rich E-mode AlGaN MOSFET for future high-power applications. [ABSTRACT FROM AUTHOR]