This application relates to the field of
semiconductor manufacturing and discloses a
photodetector and its fabrication method, comprising: a substrate; a first cladding layer located on the upper surface of the substrate; a first
waveguide located within the first cladding layer, the first
waveguide and the upper surface of the first cladding layer being flush;
graphene located on the upper surfaces of the first cladding layer and the first
waveguide; a second waveguide located on the upper surface of the
graphene; the second waveguide and the first waveguide forming a waveguide structure. The
graphene is located between the first and second waveguides, and the first and second waveguides form the waveguide structure, that is, the graphene is located within the waveguide structure. The graphene is closer to the
optical field center of the waveguide structure, which can enhance the interaction between the graphene and the
optical field and enhance the optical absorption of the graphene. This application eliminates the need for
plasma enhancement or increasing the area of the graphene, thus avoiding optical losses caused by
plasma structures and avoiding the limitation on the integration density of the
photodetector imposed by large-area graphene.