3.2.2 Task Automation

A simulation environment is a crucial component of a TCAD framework since it accomplishes an efficient and user friendly application of simulation tools. A first prototype was the VISTA TCAD Shell [58] which already integrated process and device simulation, and automated the control of the simulation tools and the management of their results. However, the sequence of simulation tools was defined at the programmer level and, therefore, a more flexible definition of the simulator sequence at the user level was desirable.

The VISTA/SFC environment [55] was a quantum leap into this direction. It's Process Flow Editor allows users the definition of the sequence of processing steps (i.e. simulation tools) and, therefore, users are able to compile the process flows and have them simulated by VISTA/SFC. Additionally, VISTA/SFC offers a lot of GUI features to watch simulations, view results, and manage simulation results. To some extent VISTA/SFC also offers support for simulation abstraction (EVE's), Design of Experiments (DOE) for Response Surface Modeling (RSM) and for automated optimization/calibration. EVE's established a common generic evaluation interface for various purposes. They served as encapsulations of process/device simulations, response surface evaluations, or arithmetic calculus. However, VISTA/SFC did not offer a simulation tool integration interface at the user level and, therefore, its users were limited to the usage of simulation tools which were already integrated. Moreover, the programming effort to implement and maintain simulation tool interfaces was high, since already existing simulation tool interfaces could not be inherited for the integration of similar new simulation tools. Nevertheless, the experiences from VISTA/SFC were extremely valuable for the implementation of the next generation. The design of SIESTA was guided by five ideas derived from VISTA/SFC:

• Create a modular simulation environment in order to extend SIESTA's life cycle.
• Offer a simulation tool interface which is configurable at the user level.
• Offer powerful job farming capabilities for computation on heterogeneous clusters of workstation.
• Refine VISTA/SFC's EVE concept for the abstraction of simulation.
• Offer a flexible support for TCAD based process and device optimization.