Self-aligned inversion n-channel In0.2Ga0.8As/GaAs metal–oxide–semiconductor field-effect-transistors with TiN gate and Ga2O3(Gd2O3) dielectric

A self-aligned process for fabricating inversion n-channel metal–oxide–semiconductor field-effect-transistors (MOSFET’s) of strained In0.2Ga0.8As on GaAs using TiN as gate metal and Ga2O3(Gd2O3) as high κ gate dielectric has been developed. A MOSFET with a 4 μm gate length and a 100 μm gate width exhibits a drain current of 1.5 mA/mm at Vg = 4 V and Vd = 2 V, a low gate leakage of <10−7 A/cm2 at 1 MV/cm, an extrinsic transconductance of 1.7 mS/mm at Vg = 3 V, Vd = 2 V, and an on/off ratio of ∼105 in drain current. For comparison, a TiN/Ga2O3(Gd2O3)/In0.2Ga0.8As MOS diode after rapid thermal annealing (RTA) to high temperatures of 750 °C exhibits excellent electrical and structural performances: a low leakage current density of 10−8–10−9 A/cm2, well-behaved capacitance–voltage (C–V) characteristics giving a high dielectric constant of ∼16 and a low interfacial density of state of ∼(2∼6) × 1011 cm−2 eV−1, and an atomically sharp smooth Ga2O3(Gd2O3)/In0.2Ga0.8As interface.