The state of the art of Technology Computer-Aided Design (TCAD) frameworks for the development of new device structures and their fabrication processes is discussed. A framework must contain support for both integration of existing simulation programs and development of new tools. The complexity and scope of a rigorous TCAD framework requires special effort to create a system which is comprehensible for both users and programmers. The implementation of the task level and user interface of the Viennese Integrated System for Technology CAD Applications (VISTA) is presented, and some important aspects of the integration of independently developed tools are discussed. Particular examples highlight the capabilities of present tools. A 0.25μm fully-planarized CMOS process with shallow trench isolation is studied. The interaction of fairly heterogeneous tools within one common environment becomes thereby transparent. As a second example, the feasibility and the limitations of ultra-low-power CMOS technologies are investigated by simulation. A set of possible ultra-low-power CMOS processes is developed and analyzed for their performance on the gate level. To demonstrate capabilities of new device structures and materials, an analysis of a High Electron Mobility Transistor (HEMT) is presented.

Process and device simulation is commonly used for the design of new VLSI devices and processes and as an explorative tool to gain a better understanding of device and process physics. On the other hand, simulation is also carried out after the design phase to optimize certain parameters of a technology, e.g., to improve device reliability or to increase the yield. For these tasks the term "Technology Computer Aided Design" or TCAD was created.

A new TCAD system is presented which is capable of performing complex development tasks by means of a powerful interaction language and an efficient database system. The integration of tools is supported by implementing it as a layered product.

This paper describes advances and remaining challenges in unstructured 3D meshing techniques for both process and device simulations and parallelization of the process simulator FLOOPS. The meshing is performed using a point cloud manager to create points and an unstructured tetrahedral mesher. Distributed parallel techniques are used to parallelize the sparse matrix assembly and solution for 3D process diffusion simulations.

With a focus on the software perspective, this paper examines benefits, scope, requirements, and key issues of the integration of Technology-CAD with Physical Design. Two examples of software components for integration of TCAD with layout data are presented, and use cases are identified which result in different software requirements. Layout data volume and its relation to domain size and resolution of TCAD models is discussed, leading to the conclusion that full-chip layout processing capabilities is a key enabling component that is becoming an integral part of mainstream TCAD.

A simple, yet efficient data structure and a generic wafer state maintenance algorithm are proposed, which unify geometry- and field-oriented representations. The implementation is based an a constrained Delaunay triangulation of the geometry and the cloud of interior mesh points which tesselates the structure with edge/triangle entities. Points are stored using a region quadtree which enables optimal O(N log(N)) performance for all range-search based operations. It is shown how this unified data structure can be equipped with generic algorithmic modules that can be applied to tool integration, to mesh generation, and to morphological solid modeling as used in topography simulation.

This paper presents a tool for initial and intermediate data processing at waferstate level. Geometric operations and analytical attribute calculations are combined with the graphical user interface and with some TCAD shell functionality to reduce the effort of both manual editing and automated operations within complex simulation flows.

Succeeding an earlier paper on the data level, the Viennese Integrated System for Technology CAD Applications (VISTA), an integration and development system for Technology CAD, is presented. Starting with a short overview of TCAD methodology and existing integrated systems, portability and comprehensibility are postulated as key considerations and an application-framework architecture is proposed. The design of VISTA's user interface and task level, presented next, adheres strictly to these guidelines. To enable the cooperation of independent simulation tools, an automatic triangulation-based service is provided by VISTA to resolve inconsistencies in wafer representations. A final example shows how three different simulators, integrated by the framework are used to simulate a planarized, trench-isolated 0.25 /spl mu/m CMOS process.< >

In order to meet the requirements of advanced process and device design, a new generation of TCAD frameworks is emerging These are based on a data level providing a common data interchange format. Such a format must be suitable for building simulation databases, and needs to be accompanied by supporting tools and by a procedural interface with multi-language bindings for data storage and retrieval by application programs. The complexity and scope of a rigorous TCAD framework requires special efforts to create a system which is both transparent to the user and comprehensible to the programmer. A consistent architecture and strict adherence to general software engineering guidelines can contribute significantly to the solution of this problem. We discuss general requirements and architectural issues of the data level, the user interface and the task level environment, and present their implementation in VISTA, the Viennese Integrated System for Technology CAD Applications.

An automatic grid design and adaption algorithm for Monte Carlo simulation of Ion Implantation (MCI') has been developed. This method has been successfully implemented in the two-dimensional process simulator PROMIS. Based on range parameters a dense initial grid is designed. Dose conservation and gradient resolution criteria are used to determine gridlines which can be deleted. Special attention has been focused on a homogenous variation of the grid spacing. The implemented algorithm produces a suitable grid for the resolution of implanted profiles, and can be successfully applied to the three-dimensional case.

Tb.e integ.ration of p.rocess and device simulato.rs into mode.rn Tecb..nology CAD (TCAD) systems bas become a necessity because of tbe inberent communication, data transfu and maint&inance advantages. Modern simulation programs and increasingly available computer resources turn complex tasks such as optimization loops into an aifordable development tool. For the consecutive invocation and combination of different simulators a unique data fo1mat as well as a common control language is 1equ.ited. Moreover, integration opens up a variety of possibilities for the design of future simulators. We shall demonstrate how to male a stand-alone simulator work in a TCAD environment. After a short description of the basic components, the paper will focus on simulator integration; linaJly, some novel insights derived from the design of the whole uameworl will be highligltted.

An implementation of a technology CAD environment is presented, using a level concept for the system: a data level provides simulation data retrieval facilities, a tool level is used for tool integration and a task level aids complex developments and user interaction.

A new TCAD system is presented, capable of performing complex development tasks by means of a powerful interaction language and an efficient database system. The integration of tools is supported through a comfortable layered application program interface