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Carrier Transport in High-Mobility III–V Quantum-Well Transistors and Performance Impact for High-Speed Low-Power Logic Applications
Dewey, G.; Hudait, M.K.; Kangho Lee; Pillarisetty, R.; Rachmady, W.; Radosavljevic, M.; Rakshit, T.; Chau, R.;
Electron Device Letters, IEEE
Volume 29,
Issue 10,
Oct. 2008
Page(s):1094
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1097
Abstract:
DC and high-frequency device characteristics of In0.7Ga0.3As and InSb quantum-well field-effect transistors (QWFETs) are measured and benchmarked against state-of- the-art strained silicon (Si) nMOSFET devices, all measured on the same test bench. Saturation current (Ion) gam of 20% is observed in the In0.7Ga0.3As QWFET over the strained Si nMOSFET at (Vg - Vt) = 0.3 V, Vds = 0.5 V, and matched Ioff, despite higher external resistance and large gate-to-channel thickness. To understand the gain in Ion, the effective carrier velocities (veff) near the source-end are extracted and it is observed that at constant (Vg - Vt) = 0.3 V and Vds = 0.5 V, the veff of In0.7Ga0.3As and InSb QWFETs are 4-5times higher than that of strained silicon (Si) nMOSFETs due to the lower effective carrier mass in the QWFETs. The product of veff and charge density (ns), which is a measure of "intrinsic" device characteristics, for the QWFETs is 50%-70% higher than strained Si at low-voltage operation despite lower ns in QWFETs. Calibrated simulations of In0.7Ga0.3As QWFETs with reduced gate-to-channel thickness and external resistance matched to the strained Si nMOSFET suggest that the higher veff will result in more than 80% Ion increase over strained Si nMOSFETs at Vds = 0.5 V, (Vg - Vt) = 0.3 V, and matched Ioff, thus showing promise for future high-speed and low-power logic applications.
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