VARIABLE CAPACITOR AND ITS MANUFACTURING METHOD

摘要

A variable capacitor having a semiconductor layer formed over a substrate with a buried oxide film interposed therebetween. In the semiconductor layer, an n-region (132) containing an n-type dopant and formed in a ring shape, an anode (133) formed in a ring shape, joined to the periphery of the n-region (132), and containing a p-type dopant, and a cathode (131) joined to the inner periphery of the n-region (132) and containing a n-type dopant are formed. The dopant concentration of the n-region (132) is lower than those of the anode (133) and cathode (131).