Submicrometer inversion-type enhancement-mode InGaAs MOSFET with atomic-layer-deposited Al2O3 as gate dielectric

High-performance inversion-type enhancementmode n-channel In0.53Ga0.47As MOSFETs with atomiclayer-deposited (ALD) Al2O3 as gate dielectric are demonstrated. The ALD process on III–V compound semiconductors enables the formation of high-quality gate oxides and unpinning of Fermi level on compound semiconductors in general. A 0.5-μm gate-length MOSFET with an Al2O3 gate oxide thickness of 8 nm shows a gate leakage current less than 10−4 A/cm at 3-V gate bias, a threshold voltage of 0.25 V, a maximum drain current of 367 mA/mm, and a transconductance of 130 mS/mm at drain voltage of 2 V. The midgap interface trap density of regrown Al2O3 on In0.53Ga0.47As is ∼1.4 × 10/cm2 · eV which is determined by lowand high-frequency capacitance–voltage method. The peak effective mobility is ∼1100 cm/V · s from dc measurement, ∼2200 cm/V · s after interface trap correction, and with about a factor of two to three higher than Si universal mobility in the range of 0.5–1.0-MV/cm effective electric field.