The previous decade witnessed the validity of semi-classical models, but questioned for more rigorous quantum transport formalisms that would become necessary to explain the behavior of charge carriers was expected with some concern. The nano-objects emerging from bottom-up nanotechnology as well as in ultra-scaled top-down nano-transistors, a new physics including quantum features has emerged and cannot be properly captured by the conventional models of device physics. For instance, in ultra-thin body (UTB) MOSFET, such as FD-SOI-FET, Fin-FET or Double-Gate (DG) MOSFET (which are considered the most promising device architectures likely to overcome shortchannel effects that dramatically affect conventional bulk-MOSFET), a silicon channel thickness smaller than 1 nm will have to be considered in the near future.
It yields a strong quantization of electron gas in a direction perpendicular to the gate stack, which results in significant changes in the space and energy distributions of particles and may be reflected in the device operation and characteristics. Furthermore, for gate length in the below sub-10 nm range, the wave-like nature of electrons may give rise to source-drain tunneling through the channel barrier and to quantum reflections in the channel.
The solution of Wigner transport equation under the influence of the potential, whose rapid space variations generate quantum effects the and its application to the study of quantum transport problems in some typical nanodevices. The technique is able to correctly treat typical situations of quantum ballistic transport (interaction of a Gaussian wave packet with a tunneling barrier), as well as semi-classical transport.
The most widely used non-equilibrium Green's function (NEGF) approach is incapable to model the carrier scattering mechanisms along with the contact modeling. Thus the Wigner function approach may be more efficient in intermediate regimes, namely in between quantum coherent and semi-classical situations, which require scattering effects to be included.
The particle-mesh coupling method is a widespread technique for space charge calculations. The spatial distribution of potential and electric field is obtained through solution of Poisson equation in TNL Particle Device Simulator (TNL-PDS) for simulation of semiconductor devices with Monte Carlo (MC) technique. The accurate computation of particle dynamics under applied electric field requires accurate solution of Poisson’s equation.
Two boundary conditions, the reflective boundary conditions are implemented in the simulator Neumann condition while the carriers hit the contact region of the device where carrier absorb and immediately re-emitted from same contact with different wave vector or from other contact to follow carrier conservation principle inside the device, Dirichlet boundary condition.
The 2D and 3D Poisson solution with tracking the super-particle in all three dimensions real space and momentum space is always cost-effective solution for advance and conventional node device technologies i.e. MOSFET, MESFET, FDSOI, TunnelFET, HEMT etc with the static and transient I-V characteristics.
