Patent ID: 7760980

Claim:
A method of fabricating on a substrate an optical detector in an optical waveguide, said method comprising: forming at least one layer on a surface of the substrate, said at least one layer comprising SiGe; implanting a first impurity in a first area through the at least one layer into a region below the at least one layer to form a contact region for the optical detector; implanting a second impurity in the first area and into the at least one layer over a first area to form a detector region for the optical detector, wherein the second impurity is different from the first impurity; after implanting the second impurity, etching into the at least one layer in a first region and a second region to form a ridge between the first and second regions, said ridge defining the optical detector and the optical waveguide; filling the first and second regions with a dielectric material having a lower refractive index than SiGe; and after filling the first and second regions with the dielectric material, removing surface material to form a planarized upper surface.