For process and device simulation, very high mesh densities are often required to obtain accurate simulation results. Unfortunately, the required mesh densities depend often on a direction. Conventional mesh-refinement strategies generate isotropic meshes with a high amount of mesh points, reaching the memory and time limits in particular for three-dimensional simulations. For a better resolution of the carrier concentrations, for instance, a boundary-conforming mesh-generation method with tunable mesh spacings in almost orthogonal directions was developed. Similar to elliptic mesh generation, the mesh points are placed inside the simulation regions based on the solution of partial differential equations. The method used can produce highly anisotropic mesh densities in the regions of particular interest. In contrast to elliptic grid generation, which produces structured grids, the method used generates triangular or tetrahedral (unstructured) Delaunay meshes in two or three dimensions, respectively, which are very well suitable for the process and device simulators.