Enhancement-Mode Antimonide Quantum-Well MOSFETs With High Electron Mobility and Gigahertz Small-Signal Switching Performance

Abstract

This letter demonstrates, for the first time, enhancement-mode (e-mode) antimonide MOSFETs by integrating a composite high-κ gate stack (3 nm Al2O3 -1 nm GaSb) with an ultrathin InAs0.7Sb0.3 quantum well (7.5 nm). The MOSFET exhibits record high electron drift mobility of 5200 cm2/V · s at carrier density (Ns) of 1.8 × 1012 cm-2, subthreshold slope of 150 mV/dec, ION/IOFF ratio of ~4000× within a voltage window of ~1 V, high ION of 40 μA/μm at VDS of 0.5 V for a 5-μm gate length (LG) device. The device exhibits excellent pinchoff in the output characteristics with no evidence of impact ionization enabled by enhanced quantization and e-mode operation. RF characterization allows extraction of the intrinsic device metrics (Cgs, Cgd, gm, veff and ft) and the parasitic resistive and capacitive elements limiting the short-channel device performance.