Vertical-type two-dimensional hole gas diamond metal oxide semiconductor field-effect transistors

Power semiconductor devices require low on-resistivity and high breakdown voltages simultaneously. Vertical-type metal-oxide-semiconductor field-effect transistors (MOSFETs) meet these requirements, but have been incompleteness in diamond. Here we show vertical-type p-channel diamond MOSFETs with trench structures and drain current densities equivalent to those of n-channel wide bandgap devices for complementary inverters. We use two-dimensional hole gases induced by atomic layer deposited Al₂O₃ for the channel and drift layers, irrespective of their crystal orientations. The source and gate are on the planar surface, the drift layer is mainly on the sidewall and the drain is the p⁺ substrate. The maximum drain current density exceeds 200 mA mm^-1 at a 12 µm source-drain distance. On/off ratios of over eight orders of magnitude are demonstrated and the drain current reaches the lower measurement limit in the off-state at room temperature using a nitrogen-doped n-type blocking layer formed using ion implantation and epitaxial growth.