Integration of Germanium avalanche photodetectors on silicon for on-chip optical interconnects

A waveguide-integrated Germanium avalanche photodetector with gain-bandwidth-product of 350GHz, sensitivity improvement of 6dB, and excess noise with keff ∼ 0.2 was demonstrated while operating with 12dB gain at around 3V bias voltage. The photodetector has capacitance of 10±2fF and operates at 40Gbps. Monolithic integration of thin single-crystalline Ge into front-end CMOS stack was achieved by rapid melt growth during source-drain implant activation anneal. ©The Electrochemical Society.