Patent ID: 11105974

Abstract:
A waveguide-coupled Silicon Germanium (SiGe) photodetector. A p-n silicon junction is formed in a silicon substrate by an n-doped silicon region and a p-doped silicon region, a polysilicon rib is formed on the silicon substrate to provide a waveguide core for an optical mode of radiation, and an SiGe pocket is formed in the silicon substrate along a length of the polysilicon rib and contiguous with the p-n silicon junction. An optical mode of radiation, when present, substantially overlaps with the SiGe pocket so as to generate photocarriers in the SiGe pocket. An electric field arising from the p-n silicon junction significantly facilitates a flow of the generated photocarriers through the SiGe pocket. In one example, such photodetectors have been fabricated using a standard CMOS semiconductor process technology without requiring changes to the process flow (i.e., “zero-change CMOS”).