A voltage variable capacitor (10) has as the base substrate a silicon wafer with a layer of high resistivity semiconductor material on top of the substrate. An insulating layer (16) of a metal oxide having a dielectric constant greater than the dielectric constant of the semiconductors (12), such as...http://www.google.es/patents/US5173835?utm_source=gb-gplus-sharePatente US5173835 - Voltage variable capacitor
