Oxygen redistribution during diffusion in thin silicon layers

During diffusion processes in thin solid layers, the usual assumption of a semi-infinite solid with constant bulk concentration is not valid. The well-known solution of the diffusion equation, based on complementary error functions, is therefore not applicable, and numerical solutions are normally used. In this work, we report an analytical solution for impurity redistribution by diffusion in thin layers. We compare the results of an explicit application of this analytical solution to oxygen out-diffusion in silicon-on-oxide structures with the experimental data, and discuss the limits of its applicability.