3.5 The Input Deck Database

State-of-the-art three-dimensional device simulators are complex software tools and challenging to control. Besides the device description loaded from a file containing the geometric definition, the grid, and the input quantities defined on the grid additional information is needed. This information is normally hierarchically structured. Circuit descriptions, models to take into account, adjustment of model parameters, material properties, circuit descriptions, simulation modes, iteration schemes, the numerical behavior, or input/output definitions must be possible. Thus, a sophisticated control system is required to allow control of each part of the simulator. The requirements for the control system have been outlined in Section 2.5.

For any control system the user-interface must be easy to learn and the user must be able to describe a simulation in a straight forward and flexible way.

The types of the additional information needed for device simulation are usually manifold:

• Values are the simplest kind of information. They are used, e.g., for model parameters, quantities, contact values, limits, or just names and strings.
• Expressions are mandatory to describe dependencies between different parameters. These expressions may be mathematical formulae or may contain logical relations and conditions.
• Sequences describe the order in which a given set of elements has to be processed.
• Hierarchies map the structures of hierarchical information. Hierarchies are used on the one hand side to describe relations between structures and on the other hand side to define the contents of a structure.

To meet these requirements a new control system called Input Deck database [K1,K2] has been developed. This database has been used to control several TCAD tools like the device simulator Minimos-NT, the Wafer-State-Library [108,109], and FEDOS (Finite Element Diffusion and Oxidation Simulator).