Patent ID: 7211875

Claim:
A semiconductor device comprising a voltage-controlled capacitive element having a variable capacitance characteristic responsive to a variable control voltage, said voltage-controlled capacitive element comprising: a first semiconductor region of a first conductivity type; second and third semiconductor regions selectively formed in said first semiconductor region apart from each other with an intervention of a part of said first semiconductor region therebetween, each of said second and third semiconductor regions being a second conductivity type, wherein each of said second and third regions has a side facing each other and said side is larger in length than a distance between said second and third regions, an insulating film formed on said part of said first semiconductor region; a conductive film formed on said insulating film; a first wiring line formed to supply a bias voltage in common to said second and third semiconductor regions, said bias voltage being different from said variable control voltage; and second and third wiring lines supplied with said variable control voltage therebetween and formed to be connected respectively to a region within said first semiconductor region and to said conductive film.