COLOR-SENSITIVE PHOTODETECTOR BASED ON POROUS SILICON SUPERLATTICES

Color-sensitivity of Si photodiodes was achieved by integrating porous silicon (PS) Bragg reflectors and Fabry-Perot filters. The PS was for med in the p(+)-type part of the p(+)n junction which required illumin ation of the samples during anodization. The optimal illumination powe r density turned out to be a compromise: high power densities are nece ssary to enable high anodization current densities, but this results i n a degraded filter performance. The PS layers had no significant infl uence on the electrical characteristics of the photodiodes, but as exp ected they strongly modified the spectral response. The results are in good agreement with the reflectance spectra of the filters. (C) 1997 Elsevier Science S.A.