Global TCAD Solutions

Next-Generation TCAD Software

VSHE (experimental)

Fig.1: Graphical user interface for VSHE in GTS Framework
Fig.1: Graphical user interface for VSHE in GTS Framework
Fig.2: Generalized electron distribution function
Fig.2: Generalized electron distribution function
Fig.3: Electron distribution function at the interface
Fig.3: Electron distribution function at the interface
Fig.4: Device / electron distribution functions
Fig.4: Device / electron distribution functions

GTS VSHE is a Framework-integrated version of ViennaSHE, an open-source project being developed at Vienna University of Technology. VSHE was added to GTS Framework to allow convenient exploring and experimenting with ViennaSHE's new algorithmic approach. However, VSHE is in experimental state, and we do not recommend production use at this time.

Boltzmann Transport Equation / SHE

ViennaSHE is a deterministic solver for the Boltzmann Transport Equation (BTE) using the spherical harmonics expansion (SHE) method. It takes into account acoustic and optical phonon scattering, ionized impurity scattering as well as a full-band dispersion relation. The approach implemented in ViennaSHE provides faster execution than Monte Carlo simulations.

Model Calibration

VSHE accurately describes the high-field transport in highly-scaled CMOS technology, hence it can be used for efficient calibration of the drift-diffusion or energy-transport model for individual devices.

Energy Distribution Function

By providing the distribution function of electrons and holes of 2D and 3D semiconductor devices, VSHE provides deeper understanding of the physical processes of semiconductor devices. For example, VSHE allows to investigate non-equilibrium carrier distribution, which is important for hot carrier degradation (high energy tail) or accurate modeling of the write process in non-volatile memory (NVRAM) devices.

Details and Example Application

For details on application, see SHE Simulation, explaining step-by-step a simulation of a 50 nm nMOS transistor.

Applications and Benefits

  • Accurate carrier transport model
  • Device model calibration (i.e. high-field mobility)
  • Energy distribution of the carriers (high energy tail)
  • Hot carrier degradation (HCD)
  • More efficient than Monte Carlo simulation

Physical models

  • Self-consistent deterministic solver for the Boltzmann transport equation
  • Acoustic and optical phonon scattering, ionized impurity scattering 
  • Fullband dispersion relation (aka. extended Vecchi model)
  • Parabolic and non-parabolic dispersion relations
  • Bipolar solution for electrons and holes including traps
  • Impact ionization scattering, electron-electron-scattering

Numerics

  • Unstructured and structured meshes in two and three dimensions
  • Multi-core support
  • GPU-enabled solver

Integrated in GTS Framework

  • Intuitive and versatile graphical user interface
  • Comprehensive scripting interface
  • Available for Windows and Linux platforms