1.2.5 Minimos-NT

Minimos-NT, first reported in 1994 by Fischer [73] and Simlinger [74], is a general purpose device simulator for analyzing arbitrary shaped devices. Within this thesis Minimos-NT was extended to a multi-dimensional device simulator capable to perform both two- and three-dimensional device simulation.

Minimos-NT solves Poisson's equation, both carrier continuity equations, the carrier energy balance equation, and the lattice heat flux equation coupled and decoupled. Moreover, transient and AC-small signal analysis can be performed. Mixed-mode simulations allow to combine physical devices and compact models in a circuit.

The simulator can handle several materials like Si, SiGe, GaAs, AlAs, InAs, InP, GaP, AlGaAs, InGaAs, InAlAs, InAsP, GaAsP, or InGaP. The numeric module consists of a direct and two different iterative linear solver where the iterative solver QQQ is applied on complex numbers which enhances AC-small signal analysis dramatically. For the solving process the user can choose among several iteration schemes to speed up the simulation and improve the convergence of the simulation.

Minimos-NT uses the PIF [75] file format introduced by Duvall. Several grid types such as ortho-product, triangular, and hybrid grids can be supplied. The number of grid nodes is only limited by the memory of the computer. The device structures to be simulated can be of arbitrary shape.

Various physical models are implemented, e.g, tunneling models like Fowler-Nordheim, Lenzlinger-Snow, Schuegraf, or Bardeen. Several generation/recombination schemes like Shockley-Read-Hall and Auger are available as well as a multitude of other physical models like band-gap-narrowing or impact ionization. A model server allows user-defined physical models to be included.