Performance and Leakage Analysis of Si and Ge NWFETs Using a Combined Subband BTE and WKB Approach

We are the first to present a subband-BTE solver with a fully integrated source/drain-tunneling current calculation based on the WKB-approximation. The method is validated against ballistic NEGF calculations showing good agreement. An investigation of Si and Ge-based NWFETs is performed showing that intra-band source/drain-tunneling is not a concern for Si devices. For Ge-based PMOS devices however, tunneling leakage limits sensible $\mathrm{L}_{\mathrm{G}}-$scaling to around 20 nm.