Ultrahigh-Speed 0 . 5 V Supply Voltage In 0 . 7 Ga 0 . 3 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 depletionmode InGaAs QW transistors with saturated transconductance gm of 930 μS/μm and fT of 260 GHz at VDS = 0.5 V are achieved on 3.2 μm 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.