Inversion-channel GaN metal-oxide-semiconductor field-effect transistor with atomic-layer-deposited Al2O3 as gate dielectric

Inversion n-channel GaN metal-oxide-semiconductor field-effect-transistors (MOSFETs) using atomic-layer-deposited Al2O3 as a gate dielectric have been fabricated, showing well-behaved drain I-V characteristics. The drain current was scaled with gate length (varying from 1 to 16 mu m), showing a maximum drain current of similar to 10 mA/mm in a device of 1 mu m gate length, at a gate voltage of 8 V and a drain voltage of 10 V. At a drain voltage of 0.1 V, a high I-on/I-off ratio of 2.5x10(5) was achieved with a very low off-state leakage of 4x10(-13) A/mu m. Both MOSFET and MOS capacitor showed very low leakage current densities of 10(-8) A/cm(2) at biasing fields of 4 MV/cm. The interfacial density of states was calculated to be (4-9)x10(11) cm(-2) eV(-1) near the midgap. (C) 2008 American Institute of Physics.