4.1 Features of

Diffusion simulation can be done on arbitrary two-dimensional geometries by using orthogonal or unstructured triangular simulation grids. Orthogonal grids are restricted to geometries with Manhattan type geometries. Built-in grid refinement algorithms are applied to the input data grids to form the initial simulation grids ensuring that some numerical quality criteria for the grids are fulfilled. With user defined algorithms one can induce additional quality criteria when needed.

The geometry of the simulated device can be partitioned into several segments connected by one-dimensional boundaries. The number of segments and boundaries is only limited by the memory resources of the computer used for the simulation. For each of the segments and boundaries different diffusion models can be defined.

The simulator is fully integrated into the *VISTA* *TCAD* environment.
The input and output format of the device descriptions is the Profile
Interchange Format *PIF* [67,29]. Therefore simulations with
*PROMIS-NT* can be integrated into a chain of other two-dimensional process
simulations within the *VISTA* environment, or by using the *tifwrap*
program [14], also into *TMA Suprem-4* [61,60] process
simulation flows.

The predefined set of quantities available for the diffusion simulation
which is compatible to the standard set of quantities available within
*TMA Suprem-4* or *VISTA* process simulations, can be replaced or extended by
an arbitrary number of user defined quantities.

Algorithms determining the initial distribution of each quantity can be
defined for each segment of the geometry. Analogously there is the
possibility to define algorithms to postprocess the quantity distributions
before writing the simulation results into the resulting *PIF* file.

The profile of the process temperature can be controlled by user defined
*MDL* functions.

1999-11-14