A Godunov-Type Stabilization Scheme for Large-Signal Simulations of a THz Nanowire Transistor Based on the Boltzmann Equation

A stabilization method is presented for the Boltzmann equation (BE) that is based on Godunov’s approach applied directly in the phase space. This makes it possible to perform transient simulations under quasiballistic conditions and to include the Pauli principle in the scattering integral without further approximations. The method ensures positive distribution functions by construction. The BE is solved self-consistently together with the Poisson and Schrödinger equations by the Newton–Raphson method for a nanowire silicon nMOSFET, for which the stationary
${I}$
–
${V}$
characteristics, the small-signal admittance parameters, and the switching behavior are calculated. The large-signal behavior of the MOSFET as an amplifier is evaluated by cyclostationary simulations including power gain and the output power at higher harmonics. The current responsivity of the MOSFET operated as a passive mixer is simulated up to terahertz (THz) frequencies including the quasiballistic case with negligible scattering.