Patent ID: 6703681
Filing Date: 2004-03-09
Classification: H01L

Abstract:
A capacitor with a variable capacitance comprising a periodic structure of areas in relief (5) separated by recesses (6) formed in a semiconductor substrate (1) of a first doping type, in which the walls of the areas in relief and the bottom of the recesses are coated with a conductive layer (9, 10), the substrate being connected to a first terminal (A) of the capacitor and the conductive layer to a second terminal (B) of the capacitor, in which at least the bottom of the recesses or the side of the areas in relief comprises regions (8) of the second doping type, the pitch of the portions in relief being selected so that the space charge areas linked to the regions of the second doping type join when the voltage difference between said terminals exceeds a determined threshold, characterized in that the areas which do not comprise the regions of the second doping type are coated with an insulator (7, 20, 30) and in that a heavily-doped region (11) of the conductivity type of the substrate is formed under the insulator.