AMORPHOUS-SILICON SENSORS FOR OXIDIZED POROUS SILICON OPTICAL WAVE-GUIDES BURIED IN SILICON-WAFERS

We have developed an original technology to fabricate channel waveguid es on monocrystalline silicon wafers, consisting of selective anodizat ion followed by thermal processing. The obtained oxidised porous silic on waveguides show waveguiding properties, moreover, due to the fabric ation process, the waveguides are placed just under the surface of the silicon wafer. A hydrogenated amorphous silicon film has been grown o n top of the waveguide by a low temperature process, then aluminum con tacts have been formed by standard lithography. Different device struc tures (photodiodes and photoresistors) are presented. Current/voltage properties in the dark and under light excitation accompanied with cap acitance/voltage measurements have been used to develop a band diagram model. (C) 1998 Elsevier Science B.V. All rights reserved.