Abstract: High-frequency performance of vertical InAs/InGaAs heterostructure nanowire MOSFETs on Si is demonstrated for the first time for a gate-last configuration. The device architecture allows highly asymmetric capacitances, which increases the power gain. A device with Lg = 120 nm demonstrates fT = 120 GHz, fmax = 130 GHz and maximum stable gain (MSG) = 14.4 dB at 20 GHz. These metrics demonstrate the state-of-the-art performance of vertical nanowire MOSFETs.