Scalability of FinFETs and Unstrained–Si/Strained–Si FDSOI–MOSFETs

Full–band Monte Carlo simulations are performed for n–type FinFETs as well as for unstrained–Si and strained–Si fully–depleted (FD) SOI–MOSFETs. Gate lengths of 50 nm down to 10 nm are considered, and a fixed off–current of 100 nA/μm is in each case ensured by adjusting the silicon film thickness. The FinFET shows the best scaling trend, but the strained–Si FDSOI–MOSFET always involves the largest absolute value for the on–current. However, the on–current decreases upon scaling to 10 nm which might stem from a larger influence of surface roughness scattering in thin Si films affecting most strongly quasi–ballistic transport in strained Si. The feature of a decreasing current is found to be absent in drift–diffusion simulation because this approach does not include quasi–ballistic transport.