Analytic representations of the dielectric functions of materials for device and structural modeling

Analytic representations of the dielectric function epsilon are needed for the analysis of optical data of complex materials and structures. Here, we examine various harmonic-oscillator-based representations of the dielectric functions of the silicon-related materials, crystalline Si, amorphous Si, and silicon nitride. For crystalline semiconductors we develop a new representation with a prefactor proportional to omega(-2), the expected response for materials with wavefunctions that are eigenfunctions of the momentum operator. (C) 1998 Elsevier Science S.A.