Substrate engineering for high-performance surface-channel III-V metal-oxide-semiconductor field-effect transistors

High-performance inversion-type enhancement-mode n-channel In0.65Ga0.35As metal-oxide-semiconductor field-effect transistors (MOSFETs) with atomic-layer-deposited Al2O3 as gate dielectric are demonstrated. A 0.5μm gate-length MOSFET with an Al2O3 gate oxide thickness of 10nm shows a gate leakage current less than 5×10−6A∕cm2 at 4V gate bias, a threshold voltage of 0.40V, a maximum drain current of 670mA∕mm, and transconductance of 230mS∕mm at drain voltage of 2V. More importantly, a model is proposed to ascribe this 80% improvement of device performance from In0.53Ga0.47As MOSFETs mainly to lowering the energy level difference between the charge neutrality level and conduction band minimum for In0.65Ga0.35As. The right substrate or channel engineering is the main reason for the high performance of the devices besides the high-quality oxide-semiconductor interface.