Abstract
High-performance inversion-type enhancement-mode n -channel In 0.65 Ga 0.35 As metal-oxide-semiconductor field-effect transistors (MOSFETs) with atomic-layer-deposited Al 2 O 3 as gate dielectric are demonstrated. A 0.5 μ m gate-length MOSFET with an Al 2 O 3 gate oxide thickness of 10 nm shows a gate leakage current less than 5 × 10 − 6 A ∕ cm 2 at 4 V gate bias, a threshold voltage of 0.40 V , a maximum drain current of 670 mA ∕ mm , and transconductance of 230 mS ∕ mm at drain voltage of 2 V . More importantly, a model is proposed to ascribe this 80% improvement of device performance from In 0.53 Ga 0.47 As MOSFETs mainly to lowering the energy level difference between the charge neutrality level and conduction band minimum for In 0.65 Ga 0.35 As . The right substrate or channel engineering is the main reason for the high performance of the devices besides the high-quality oxide-semiconductor interface.