Halbleiterfotodiode

The invention relates to a semiconductor photodiode comprising a light-absorbing layer (111); an optical waveguide (12) by means of which the light (L) can be coupled into said light-absorbing layer (111) in an evanescent manner; and a doped contact layer (113) arranged between said light-absorbing layer (111) and optical waveguide (12). According to the invention, the optical waveguide (12) is doped in at least some sections generating a diffusion barrier that counteracts diffusion of the dopant of the contact layer (113) into the optical waveguide (12). The invention also relates to a method for producing a semiconductor photodiode.