A SYSTEM FOR 3D SIMULATION OF COMPLEX SI AND HETEROSTRUCTURE DEVICES

A software package has been developed for simulating complex silicon a nd heterostructure devices in 3D. Device geometries are input with a m ouse-driven geometric modeler, thus simplifying the definition of comp lex 3D shapes. Single components of the device are assembled through b oolean operations. Tetrahedra are used for grid generation, since any plane-faced geometry can be tessellated with tetrahedra, and point den sities can be adapted locally. The use of a novel octree-like data str ucture leads to oriented grids where desirable. Bad angles that preven t the convergence of the control volume integration scheme are elimina ted mostly through topological transformations, thus avoiding the inse rtion of many redundant grid points. The discretized drift-diffusion e quations are solved with an iterative method, using either a decoupled (or Gummel) scheme, or a fully coupled Newton scheme. Alternatively, generated grids can be submitted to a Laplace solver in order to calcu late wire capacitances and resistances. Several examples of results il lustrate the flexibility and effectiveness of this approach.