Patent ID: 8294882

Claim:
A photonic mixer provided with a semiconductor substrate having a field area and means for generating a majority carrier current and an associated electric field in the semiconductor substrate that is doped with a first conductivity type, such that when electromagnetic radiation impinges on the substrate within said field area, pairs of majority and minority carriers are generated in the substrate, resulting in a photocurrent of the minority carriers, said substrate comprising a couple of an injecting contact region for injecting the majority carrier current into the semiconductor substrate and a detector region for collecting the photocurrent, which injecting contact region is doped with a dopant of the first conductivity type at a higher dopant concentration than the semiconductor substrate, and which detector region is doped with a dopant of a second conductivity type opposite to the first conductivity type and that has a junction with the semiconductor substrate, a zone of the semiconductor substrate around said junction being a depleted substrate zone, wherein said couple further comprises a field shaping zone of the first conductivity type defining a lateral edge of the couple and having a dopant concentration higher than the dopant concentrations of the semiconductor substrate, wherein the field shaping zone is designed to limit said depleted substrate zone laterally.