Abstract: The invention relates to a method of manufacturing a varicap diode whereby a silicon substrate with an epitaxial layer of a first conductivity type is provided with a first zone through the provision of dopant atoms of a first conductivity type in the epitaxial layer and is provided with a second zone adjoining a surface of the epitaxial layer through the provision of dopant atoms of a second conductivity type opposed to the first in the epitaxial layer, a pn junction being formed between the second zone and the first zone. According to the invention, the method is characterized in that the second zone is provided in that a layer of polycrystalline silicon provided with dopant atoms of the second conductivity type is provided on the surface, and in that the dopant atoms are diffused from this layer into the epitaxial layer, whereby a pn junction is formed at a distance of less than 0.3 .mu.m from the polycrystalline silicon.