Small-Signal Performance and Modeling of sub-50nm nMOSFETs with f above 460-GHz.

We have fabricated and tested the performance of sub-50nm gate nMOSFETs to assess their suitability for mixed signal applications in the super high frequency (SHF) band, i.e. 3-30GHz. For a 30nm×40 μm×2 device, we found f(T) =465GHz at V(ds)=2V, V(g)=0.67V, which is the highest cut-off frequency reported for a MOSFET produced on bulk silicon substrate so far. However, our measurements of f(max) and noise figure indicate that parasitics impose limitations on SHF operation. We also present a high-frequency ac model appropriate to sub-50nm gate length nanotransistors, which incorporates the effects of the parasitics. The model accurately accounts for measurements of the S and Y parameters in the frequency range from 1 to 50GHz.