Abstract
In this paper we present the integration of an InP-based photodetector with silicon-on-insulator (SOI) waveguides using thermocompression bonding. A BCB prism integrated on top of the light-sensitive area of a planar detector (PD) chip deflects the light from a 4 m thick SOI waveguide upward into the flip-chip bonded PD. A trench is etched in front of the SOI waveguide to accommodate prisms with apexes up to 7 m. Using thermocompression bonding between thin gold pads (500 nm thickness) deposited on both, SOI and photodetector chips an excellent vertical alignment accuracy of ±100 nm can be achieved, limited only by etching and Au-deposition tolerances. A commercial flip-chip bonder provides a lateral alignment accuracy also in the sub-micron range. Together with a previously developed process for integrating lasers and SOA chips using the same technology, fully functional PICs can now be realized on the SOI platform using thermocompression bonding.