Carrier Transport in High-Mobility III-V Quantum-Well Transistors and Performance Impact for High-Speed Low-Power Logic Applications.

DC and high-frequency device characteristics of In[sub0.7]Ga[sub0.3]As 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 (I[subon]) gain of 20% is observed in the In[sub0.7]Ga[sub0.3]As QWFET over the strained Si nMOSFET at (V[subg] - V[subt]) = 0.3 V, V[subds] = 0.5 V, and matched I[suboff], despite higher external resistance and large gate-to-channel thickness. To understand the gain in I[subon], the effective carrier velocities (V[subeff]) near the source-end are extracted and it is observed that at constant (V[subg] - V[subt]) = 0.3 V and V[subds] = 0.5 V, the V[subeff] of In[sub0.7]Ga[sub0.3]As and InSb QWFETs are 4-5x higher than that of strained silicon (Si) nMOSFETs due to the lower effective carrier mass in the QWFETs. The product of V[subeff] and charge density (n[sub8]), which is a measure of "intrinsic" device characteristics, for the QWFETs is 50%-70% higher than strained Si at low-voltage operation despite lower n[sub8] in QWFETs. Calibrated simulations of In[sub0.7]Ga[sub0.3]As QWFETs with reduced gate-to-channel thickness and external resistance matched to the strained Si nMOSFET suggest that the higher V[subeff] will result in more than 80% I[subon] increase over strained Si nMOSFETs at V[subds] = 0.5 V, (V[subg] - V[subt]) = 0.3 V, and matched I[suboff], thus showing promise for future high-speed and low-power logic applications. [ABSTRACT FROM AUTHOR]