OPTICAL-PROPERTIES OF THIN-FILM SILICON-COMPATIBLE MATERIALS

The optical performance of photodetectors in silicon strongly depends on the transmission of incident light into Si and the charge collectio n efficiency therein. Consequently, improving the transmission efficie ncy of light into Si by means of an interference antireflectant (AR) f ilter can lead to improved optoelectric conversion efficiency. However , the design of these filters requires the availability of data on the optical characteristics of the materials used. Furthermore, for the r ealization of such filters for light detectors realized in silicon, th e required compatibility with standard microelectronic processing impl ies that only Si-compatible materials should be used. The range of suc h Si-compatible materials available for fabricating photoelectric devi ces in silicon includes thermally grown SiO2, low-pressure chemical-va por deposited polysilicon, silicon nitride (low stress and stoichiomet ric), and oxides (low-temperature oxide, phosphosilicate glass, borosi licate glass, borophosphosilicate glass) as well as plasma-enhanced ch emical-vapor deposited oxynitrides. We present the refractive index an d the extinction coefficient of these materials in the 380-800-nm rang e. The data presented enhance the accuracy and applicability of simula tion and design tools used to design photodetectors in silicon for the visible range. (C) 1997 Optical Society of America.