Gd 2 O 3 / GaN metal-oxide-semiconductor field-effect transistor

${\mathrm{Gd}}_2{\mathrm{O}}_3$ has been deposited epitaxially on GaN using elemental Gd and an electron cyclotron resonance oxygen plasma in a gas-source molecular beam epitaxy system. Cross-sectional transmission electron microscopy shows a high concentration of dislocations which arise from the large lattice mismatch between the two materials. GaN metal-oxide-semiconductor field-effect transistors (MOSFETs) fabricated using a dielectric stack of single crystal ${\mathrm{Gd}}_2{\mathrm{O}}_3$ and amorphous ${\mathrm{SiO}}_2$ show modulation at gate voltages up to 7 V and are operational at source drain voltages up to 80 V. This work represents demonstrations of single crystal growth of ${\mathrm{Gd}}_2{\mathrm{O}}_3$ on GaN and of a GaN MOSFET using ${\mathrm{Gd}}_2{\mathrm{O}}_3$ in the gate dielectric.