Automatic Grid Generation for 3 d Device Simulation

The concepts of an automatic 3d grid generator for the solution of the semiconductor equations are presented. The grid generator allows to mix elements of different shapes. An algorithm for the refinement of a grid according to a given point density function is outlined. Local heuristics for the improvement of the quality of the elements with worst aspect ratio obtained during the refinement are discussed. The data structure used to represent the grids is a boundary representation optimized to retrieve the neighborhood informations used in finite element assembly. Points and elements can be added and deleted in constant time.