High-performance GaAs-based metal-oxide-semiconductor heterostructure field-effect transistors with atomic-layer-deposited Al_2O_3 gate oxide and in situ AlN passivation by metalorganic chemical vapor deposition

摘要

GaAs-based metal-oxide-semiconductor heterostructure field-effect transistors (MOSHFETs) with Al_2O_3 gate oxide and in situ AlN passivation were investigated. Passivation with AlN improved the quality of the MOS interfaces, leading to good control of the gate. The devices had a sufficiently small subthreshold swing of 84 mV decade"1 in the drain current vs gate voltage curves, as well as negligible frequency dispersions and nearly zero hysteresis in the gate capacitance vs gate voltage curves. A maximum drain current of 630 mA/mm and a peak effective mobility of 6720 cm~2 V~(-1) s~(-1) at a sheet carrier density of 3 × 10~(12) cm~2 were achieved.