HIGH FREQUENCY VOLTAGE-VARIABLE CAPACITOR

A voltage-variable capacitor having a relatively high figure of merit, Q, and thus useful at relatively high frequencies, includes a thin layer of epitaxial semiconductive material on a highly doped semiconductor substrate. An apertured dielectric layer is disposed on the epitaxial layer and a layer of material capable of making rectifying contact to the semiconductive material is disposed on the dielectric layer, with a portion thereof extending into an aperture in the dielectric layer into rectifying contact with the epitaxial layer. This construction eliminates the need for a diffused, minority-carrier-collecting junction, thereby allowing the epitaxial layer to be thin and the series resistance of the device to be low.