Integration Of SiON waveguides and photodiodes on silicon substrates

Two methods of coupling integrated optical waveguides to photodetectors are investigated. As waveguides, SiON layers were deposited by low-pressure chemical vapor deposition on a thick isolation layer of thermally grown SiO(2) on silicon substrates. Lateral p-i-n diode photodetectors were fabricated by standard processing in the silicon substrates. Structures for end-fire and leaky-wave coupling were fabricated. Coupling efficiencies of up to 84% for end-fire and 88% for leaky-wave coupling were obtained. The fabrication steps are described, and the resulting optoelectrical behavior is discussed.