Semiconductor varactor device and electronic tuner using same

Abstract

A varactor device comprised of plural varactor elements disposed in a semiconductor body, each varactor element includes first and second semiconductor regions defining a PN junction therebetween. Any two of the varactor elements in the semiconductor body are separated from each other by semiconductor material of one conductivity type. Electrodes are provided on the semiconductor material of one conductivity type and on the plural varactor elements. Individual conductors are provided on the respective electrodes. In accordance with this construction, the electrodes on the semiconductor material are adapted to be supplied with a predetermined potential to substantially shield the varactor elements and minimize stray capacitance therebetween. In one preferred application of the varactor device, it is used with a tuner, such as a UHF tuner, such that the variable capacitance of the varactor device changes the frequency to which the tuner is tuned. The tuner includes electrical shielding members which are mechanically coupled to, and in electrical contact with the semiconductor body of the varactor device. An electrical conductor connects at least one of the varactor electrodes to a respective signal processing stage in the tuner.