Fmax enhancement of dynamic threshold-voltage MOSFET (DTMOS) under ultra-low supply voltage

The high frequency characteristics of DTMOS are described here for the first time. Our DTMOS has a small parasitic resistance due to an optimized Co salicide technology and a small parasitic capacitance due to a reduction in the overlapped region between the gate and drain, which is achieved by gate poly-Si oxidation before LDD implantation. We obtained an Ft of 78 GHz and an Fmax of 3.7 GHz for a 0.1-/spl mu/m-Leff DTMOS even at a supply voltage of 0.7 V. We also noted an Fmax enhancement of 1.5 times compared to that of a conventional SOI MOSFET, which is attributed to a high transconductance and a large output resistance.