Abstract: A process for producing a photodiode sensitive to infrared radiation, obtained by the planar technique, constituted by a semiconducting material comprising a substrate of type p (or n) and a zone of type n (or p) forming the junction, wherein a thin layer is deposited on the substrate surface by a per se known process, the said thin layer being constituted by a compound whose constituents are taken from among those of the substrate, whereby the proportions thereof are the same or close to those of the said substrate, a dielectric protective layer is deposited on the said thin layer, the material thus obtained is thermally treated, a diffusion of the zone of the other type is effected in order to form the junction and local deposits of metal are made on the surface of the said dielectric layer.