Abstract: The numerical solution to one-dimensional Poisson's equation for MIS structures is described in detail in this paper. Newton's iterated formulation for a nonuniform mesh is derived and the suitable boundary conditions for MIS structures are also presented. As an example of the application of the numerical method, the Ψ_S-V_G relation and the interface trap density are obtained by use of the high frequency C-V characteristic for a MOS structure whose SiO₂ film is thermally grown. This method is compared with the quasi-static method experimentally. The results are well agreed, but the former method is much simpler in fabricating and measuring the example. Therefore, this method is suitable for the regular process monitoring.

Key words: surface potential, numerical method, interface trap density, Poisson's equation, MIS structure