Interface Traps in InAs Nanowire Tunnel-FETs and MOSFETs-Part I: Model Description and Single Trap Analysis in Tunnel-FETs

This paper and the companion work present a full quantum study of the influence of interface traps on the I-V characteristics of InAs nanowire Tunnel-field effect transistors (FETs) and MOSFETs. To this purpose, we introduced a description of interface traps in a simulator based on non equilibrium Green's function formalism, employing an 8x8 k.p Hamiltonian and accounting for phonon-scattering. In our model, traps can affect the I-V curves of the transistors both by modifying the device electrostatics and by directly participating the carrier transport. This paper investigates the impact of single trap on the I-V characteristics of Tunnel-FETs by varying the trap energy level, its volume and position, as well as the working temperature. Our 3-D self-consistent simulations show that: 1) even a single trap can deteriorate the inverse subthreshold slope of a nanowire InAs Tunnel-FET; 2) shallow traps have the largest impact on subthreshold slopes; and 3) the inelastic phonon-assisted tunneling through interface traps results in a temperature dependence of the otherwise temperature-independent Tunnel-FETs I-V characteristics.