Modified Poisson solver for the simulation of the silicon-oxide interface in semiconductor detectors

We present a modified Poisson solver for depleted semiconductor detectors t hat takes into account the effects of possible accumulation of mobile charg e at the silicon-oxide interfaces. The solver is based on a physical model that closely approximates the correct boundary condition at the silicon-oxi de interface. The model assumes that the silicon-oxide interface is divided into an equipotential region, where the electron layer is located, and a f ully depleted region. The actual extension and potential of the electron la yer region are approximated with the desired accuracy by an iterative proce dure. This model has been implemented in 2- and 3-D Poisson solvers. The co mparison with a 2-D drift-diffusion simulator has shown the accuracy of the proposed method. The modified Poisson solver has shown to be useful in giv ing accurate solutions to 3-D design problems at high CPU speed. (C) 2000 E lsevier Science B.V. All rights reserved.