We present the Vienna Schrödinger-Poisson Solver (VSP), a multi-purpose quantum mechanical solver for investigations on nano-scaled device structures. VSP includes a quantum mechanical solver for closed as well as open boundary problems on fairly arbitrary one-dimensional cross sections within the effective mass framework. For investigations on novel gate dielectrics VSP holds models for bulk and interface trap charges, and direct and trap assisted tunneling. Hetero-structured semiconductor devices, like resonant tunneling diodes (RTD), can be treated within the closed boundary model for quick estimation of resonant energy levels. The open boundary model allows evaluation of current voltage characteristics.

In order to facilitate the rational design and the characterization of nanowire field-effect sensors, we have developed a model based on self-consistent charge-transport equations combined with interface conditions for the description of the biofunctionalized surface layer at the semiconductor/electrolyte interface. Crucial processes at the interface, such as the screening of the partial charges of the DNA strands and the influence of the angle of the DNA strands with respect to the nanowire, are computed by a Metropolis Monte Carlo algorithm for charged molecules at interfaces. In order to investigate the sensing mechanism of the device, we have computed the current–voltage characteristics, the electrostatic potential and the concentrations of electrons and holes. Very good agreement with measurements has been found and optimal device parameters have been identified. Our approach provides the capability to study the device sensitivity, which is of fundamental importance for reliable sensing.

We perform a comparative study of various macroscopic transport models against multisubband Monte Carlo (MC) device simulations for decananometer MOSFETs in an ultrathin body double-gate realization. The transport parameters of the macroscopic models are taken from homogeneous subband MC simulations, thereby implicitly taking surface roughness and quantization effects into account. Our results demonstrate that the drift-diffusion (DD) model predicts accurate drain currents down to channel lengths of about 40 nm but fails to predict the transit frequency below 80 nm. The energy-transport (ET) model, on the other hand, gives good drain currents and transit frequencies down to 80 nm, whereas below 80 nm, the error rapidly increases. The six moments model follows the results of MC simulations down to 30 nm and outperforms the DD and the ET models

The characteristics of modern semiconductor devices are strongly influenced by quantum mechanical effects. Due to this fact, purely classical device simulation is not sufficient to accurately reproduce the device behavior. For instance, the classical semiconductor equations have to be adapted to account for the quantum mechanical decrease of the carrier concentration near the gate oxide. Several available quantum correction models are derived for devices with one single inversion layer and are therefore only of limited use for thin double gate (DG) MOSFETs where the two inversion layers interact. We present a highly accurate quantum correction model which is even valid for extremely scaled DG MOSFET devices. Our quantum correction model is physically based on the bound states that form in the Si film. The eigenenergies and expansion coefficients of the wave functions are tabulated for arbitrary parabolic approximations of the potential in the quantum well. Highly efficient simulation of DG MOSFET devices scaled in the decananometer regime in TCAD applications is made possible by this model.