Diamond exhibits large application potential in the field of power electronics, owing to its excellent and desirable electronic properties. However, the main obstacles to its development originate from the small-sized single-crystal wafers and the instability of the electrical conductivity. This work presents a metal-oxide-semiconductor field-effect transistor (MOSFET) on a diamond substrate derived from a five-inch (110) highly preferred polycrystalline diamond film. The MOSFETs with excellent performance are fabricated by combining an H-terminated channel and an epitaxially grown boron-doped layer as the source/drain contacts of the diamond devices. According to the electrical statistical results of ≈110 devices on the polycrystalline diamond substrate, 44% of devices show normally-off operation with a maximum current density of 400 mA mm−1, while 56% of devices demonstrate normally-on operation with a maximum current density of 525 mA mm−1. The normally-off characteristics are more related to the higher amounts of nitrogen concentration than the grain boundaries. The stable boron-doped source and drain provide a high concentration of holes, which facilitate transport in the surface p-type channel induced by the H-termination. The characteristics of the MOSFETs are inspiring for the fabrication of complementary inverter circuits on large diamond wafers.
- metal-oxide-semiconductor field-effect transistor (MOSFET)
- normally-off/normally-on devices
- polycrystalline diamond
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials