A Self-Aligned InGaAs Quantum-Well Metal–Oxide–Semiconductor Field-Effect Transistor Fabricated through a Lift-Off-Free Front-End Process

We present a novel n-type InGaAs quantum-well metal?oxide?semiconductor field-effect transistor (QW-MOSFET) fabricated by a self-aligned gate-last process and investigate relevant Si-like manufacturing issues in future III?V MOSFETs. The device structure features a composite InP/Al2O3 gate barrier with a capacitance equivalent thickness (CET) of 3 nm and non alloyed Mo ohmic contacts. We have found that RIE introduces significant damage to the intrinsic device resulting in poor current drive and subthreshold swing. The effect is largely removed through a thermal annealing step. Thermally annealed QW-MOSFETs exhibit a subthreshold swing of 95 mV/dec, indicative of excellent interfacial characteristics. The peak mobility of the MOSFET is 2780 cm2 V-1 s-1.