Contour Meshing With a One Dimensional Remeshing Scheme for the Simulation ' of MOS Source / Drain Diffusion

The initial mesh is constructed by using the concentration contours of the 2-D as implanted profile. Mesh spacing is chosen after making some 'a priori' estimates of the maximum diffusion which can occur during the specific anneal. As the source/drain profile evolves in time new mesh points are introduced by comparing the concentration ratio of adjacent nodes. This is an appropriate parameter as the diffusion co-efficient is proportional to concentration at most for the commonly used diffusion models. The remeshing test is only carried out along mesh lines which intersect the concentration contours and is hence a one dimensional test for a two dimensional diffusion. Application of the remeshing schemes to test problems of high concentration As diffusion indicate a halving of CPU time can be achieved when compared to a solution based entirely on a static mesh.