Hydrogen-Terminated Diamond MOSFETs Using Ultrathin Glassy Ga₂O₃Dielectric Formed by Low-Temperature Liquid Metal Printing Method

The p-type surface conductivity of hydrogen-terminated diamond (H-diamond) provides a viable approach toward diamond-based wide-bandgap metal-oxide-semiconductor field-effect transistors (MOSFETs) for high-power and high-frequency electronics. A facile, low-cost, and low-temperature method to form gate dielectrics on diamond that also preserves the integrity of hydrogen-termination is highly desirable for high-performance diamond surface electronics with process flexibility and high yield. In this work, we demonstrate a p-channel diamond MOSFET with an ultrathin glassy Ga2O3 dielectric layer derived from liquid metal. A liquid metal printing method was employed to transfer an amorphous Ga2O3 layer over the desired active p-channel region of H-diamond at low temperature, allowing the protection and preservation the hydrogen-terminated surface while also forming an efficient gate dielectric. The results of this work suggest that the liquid metal method can provide an efficient, low-cost, and high-yield pathway to form high-quality dielectrics for diamond-based transistors.