Ultrahigh-Speed 0.5 V Supply Voltage $\hbox{In}_{0.7} \hbox{Ga}_{0.3}\hbox{As}$ Quantum-Well Transistors on Silicon Substrate

The direct epitaxial growth of ultrahigh-mobility InGaAs/InAlAs quantum-well (QW) device layers onto silicon substrates using metamorphic buffer layers is demonstrated for the first time. In this letter, 80 nm physical gate length depletion-mode InGaAs QW transistors with saturated transconductance
gm
of 930 muS / mum and
fT
of 260 GHz at V
_DS
= 0.5 V are achieved on 3.2 mum thick buffers. We expect that compound semiconductor-based advanced QW transistors could become available in the future as very high-speed and ultralow-power device technology for heterogeneous integration with the mainstream silicon CMOS.