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

This letter demonstrates, for the first time, enhancement-mode (e-mode) antimonide MOSFETs by integrating a composite high-k 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 cm(2)/V . s at carrier density (N-s) of 1.8 x 10(12) cm(-2), subthreshold slope of 150 mV/dec, I-ON/I-OFF ratio of similar to 4000x within a voltage window of similar to 1 V, high I-ON of 40 mu A/mu m at V-DS of 0.5 V for a 5-mu m gate length (L-G) 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 (C-gs, C-gd, g(m), g(ds), v(eff), and f(t)) and the parasitic resistive and capacitive elements limiting the short-channel device performance.