High performance dual-gate SiGe MOSFET for radio-frequency applications

In this paper, we propose a new Si0.6Ge0.4 n-channel dual-gate metal-oxide-semiconductor field-effect transistor (DGMOS) structure for high frequency small signal applications. The gate length of the device is 60 nm and gate-oxide (SiO2) thickness is 2 nm with n+ poly-silicon as gate material. Both the gates of DGMOS are placed in the oxide-filled trenches leading to formation of dual conduction channels which enhances the drive current, gain and frequency response. Two-dimensional simulation tool (ATLAS) is used to analyse and compare the performance of the proposed structure with conventional device. The DGMOS provides 5.35 times higher current drivability, 306% improvement in peak transconductance, 114% enhancement in unity current gain cut-off frequency and 3.75 times higher oscillation frequency with good control of short channel effects in comparison to the conventional MOSFET.