Patent ID: 6541814
Filing Date: 2003-04-01
Classification: H01L

Abstract:
A variable capacitor comprising:a gate formed over a thin insulator that separates the gate from a substrate; a source formed in the substrate on a source side of the gate; an upper-source contact to the source for applying an upper voltage to an upper portion of the source; and a lower-source contact to the source for applying a lower voltage to a lower portion of the source; wherein the upper voltage is higher than the lower voltage, wherein a gate-to-source voltage varies along a gate-source edge; wherein a gate bias voltage applied to the gate, the upper voltage and the lower voltage cause a conducting portion of the gate to have a conducting channel formed in the substrate under the conducting portion, and a non-conducting portion of the gate to not have a conducting channel formed in the substrate under the non-conducting portion; wherein a capacitance per unit area of the conducting portion is higher than a capacitance per unit area of the non-conducting portion; wherein capacitance of the variable capacitor measured from the gate is adjustable by adjusting a ratio of an area of the conducting portion to the area of the non-conducting portion, whereby capacitance is adjustable by adjusting areas of conducting and non-conducting regions under the gate.