This paper outlines the modeling requirements of integrated circuit (IC) fabrication processes that have lead to and sustained the development of computer-aided design of technology (i. e. TCAD). Over a period spanning more than two decades the importance of TCAD modeling and the complexity of required models has grown steadily. The paper also illustrates typical applications where TCAD has been powerful and strategic to IC scaling of processes. Finally, the future issues of atomic-scale modeling and the need for an hierarchical approach to capture and use such detailed information at higher levels of simulation are discussed.

In this paper, a three part algorithm is employed to obtain stable convergence during stress dependent oxidation simulation using the finite element method is presented. By introducing (1) a reduced integration formulation, (2) an averaging procedure for the mid-side node velocities at the Si/SiO2 interface, and (3) a three-node element to discretize the oxidant diffusion equation, major improvements in achieving stable convergence are realized during stress dependent oxidation simulation. This technique is generally applicable for an oxidation simulator using the finite element method.

As wireless communication is penetrating every corner of the globe, the optimum design and accurate analysis of RF, power semiconductor devices become one of the biggest challenges in EDA and TCAD (Technology CAD) tool development. The performance gauge for these devices is quite different from that for either digital or analog devices aimed at small-signal applications in that the power gain, efficiency, and distortion (or the range of linearity) are the utmost design concerns. In this article, the methodology and mathematical foundation for numerical analysis of large signal distortion at the device simulation level are discussed. Although the harmonic balance (HB) method has long been used in circuit simulation for large signal distortion analysis, the implementation of the same method in device simulation faces daunting challenges, among which are the tremendous computational cost and memory storage management. But the benefits from conducting such a device level simulation are also obvious--for the first time, the impact of technology and structural variation of device on large signal performance can directly be assessed. The necessary steps to make the HB analysis feasible in device simulation are outlined and algorithmic improvement to ease the computation/storage burden is discussed. The applications of the device simulator for various RF power devices, including GaAs MESFETs and silicon LDMOS (lateral diffusion MOS) are presented, and the insight gained from such an analysis is provided.

Numerical simulation of the hydrodynamic semiconductor device equations requires powerful numerical schemes. A Space-time Galerkin/Least-Squares finite element formulation, that has been successfully applied to problems of fluid dynamic, is proposed for the solution of the hydrodynamic device equations. Similarity between the equations of fluid dynamic and semiconductor devices is discussed. The robustness and accuracy of the numerical scheme are demonstrated with the example of a single electron carrier submicron silicon MESFET device.