Realistic device simulation in three dimensions (EPROM cell)

The simulation of a realistic floating-gate EPROM (electrically programmable ROM) cell is carried out by the three-dimensional device simulator HFIELDS 3-D. The results obtained are in good agreement with measurements, because of the accurate description of both the device geometry and the impurity profile. The latter, in turn, is made possible by the adoption of a prism-based discretization scheme (which allows remarkable simplification of mesh and geometry management) and by extrapolating 2-D process simulation results. The critical amount of computations is faced by using iterative linear solvers which make it possible to keep CPU time reasonably low. Qualitatively relevant differences between 2-D- and 3-D-computed results are highlighted, related to the channel-width modulation due to the applied gate voltage.<>