Investigation of thin InN/GaN heterostructures with in situ SiNx dielectric grown by plasma-assisted molecular beam epitaxy

The effects of InN layer thickness (4/7/10 nm) in metal-insulator-semiconductor Ni/SiNx/InN structures have been evaluated. The 7 nm thick SiNx layer is deposited in situ, by plasma assisted molecular beam epitaxy, on the surface of InN grown on GaN (0001) buffer layers. Metal-insulator-semiconductor capacitors (MISCAPs) and InN channel field-effect transistors (MISFETs) were fabricated and the electrical characteristics of the devices were studied and discussed. Room temperature current versus voltage analysis of the MISCAPs suggested ohmic conduction by hopping at low electric fields, while field emission was prevailed for high electric fields with an extracted trap barrier height in the range of 1.1-1.3 eV for all the structures. The output characteristics of the fabricated MISFETs showed modulation of the drain-source current with the highest current density of 0.8 A/mm for the 10 nm InN layer, but the channel could not fully pinch-off. (C) 2017 American Vacuum Society.