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Ballistic transport in monolayer Germanane MOSFETs is investigated for high-performance (HP) applications. Characteristics of both n- and p-type transistors having channel lengths of 7, 5, and 3 nm are studied and compared against the International Technology Roadmap for Semiconductor (ITRS) target of 2028. Our simulation approach is based on a self-consistent quantum ballistic transport model within the framework of the nonequilibrium Green’s function formalism and relies on a single-band and a two-band ${k}\cdot {p}$ Hamiltonian for n- and p-type channels, respectively. We found that, even for a gate length scaled down to 3 nm, the ON current ( ${I}_{ \mathrm{\scriptscriptstyle ON}}$ ) in n- and p-MOSFETs for a fixed OFF current ${I}_{ \mathrm{\scriptscriptstyle OFF}} =100\,\,{\text nA/\mu m}$ is as high as ~890 and 700 $\mu \text {A}/\mu \text {m}$ , respectively. For longer channel lengths, the p-MOSFET can outperform the n-MOSFET in terms of ${I}_{ \mathrm{\scriptscriptstyle ON}}$ requirements, as the direct source-to-drain tunneling gets suppressed. Other performance metrics, including gate capacitance, intrinsic switching delay, and switching energy, have also been calculated and found to be comparable to the ITRS 2028 HP technology requirements.

In this paper, we present a full 3-D real-space quantum-transport simulator based on the Green's function formalism developed to study nonperturbative effects in ballistic nanotransistors. The nonequilibrium Green function (NEGF) equations in the effective mass approximation are discretized using the control-volume approach and solved self-consistently with the Poisson equation in order to obtain the electron and current densities. An efficient recursive algorithm is used in order to avoid the computation of the full Green function matrix. This algorithm, and the parallelization scheme used for the energy cycle, allow us to compute very efficiently the current-voltage characteristic without the simplifying assumptions often used in other quantum-transport simulations. We have applied our simulator to study the effect of surface roughness and stray charge on the ID-VG characteristic of a 6-nm Si-nanowire transistor. The results highlight the distinctly 3-D character of the electron transport, which cannot be accurately captured by using 1-D and 2-D NEGF simulations, or 3-D mode-space approximations.