Mobility of holes in gated conduction channels of hydrogenated diamond heterostructures

The physical characteristics of diamond, such as high thermal conductivity of 23 W/cmK and high breakdown field of 13 MV/cm suggest that diamond is a promising semiconductor material for high power operation. The goal of this work is to evaluate mobility of holes in transferer-doped diamond based quasi-two-dimensional conduction channels formed at the hydrogenated diamond surfaces and at the interfaces of diamond / polar dielectric heterostructures, in order to enable modeling and characterization of diamond transistors. The mobile holes are electrostatically quantum-confined within a few nanometers near the interface and their mobility is bounded by Coulomb scattering from fixed negative charges and interaction with phonons, including interface polar optical phonons. We find weak dependence of mobility on channel-to-gate distance, but strong dependence on channel-to-fixed charges distance. We also evaluated the effect of the carrier scattering by the polar BN phonons at the diamond/BN interface on mobility. In high carrier density channels, we find that the scattering by the interface phonons is weak due primarily to the Pauli blocking in the final states available for the scattered mobile holes. The band parameters used in our work were found from performing DFT calculations.