Patent ID: 7704845
Filing Date: 2010-04-27
Classification: H01L

Abstract:
1. A method for manufacturing a varactor, the method comprising the steps of: forming a first well by implanting a first conductive-type ion onto a substrate; forming a first ion implantation area by implanting a second conductive-type ion into the first well; forming a first epitaxial layer on the substrate, including the first ion implantation area; forming a first plug by implanting second conductive-type ions into a portion of the first epitaxial layer, in which the first plug is electrically connected to the first ion implantation area; forming a second well by implanting ions into the first epitaxial layer; forming a second ion implantation area by implanting second-conductive type ions into the second well; forming a second epitaxial layer on the first epitaxial layer having the second ion implantation area therein; forming a plurality of isolation areas in the second epitaxial layer; forming a third well by implanting first conductive-type ion into the second epitaxial layer; forming a second plug by implanting second conductive-type ions onto a portion of the second epitaxial area, in which the second plug is electrically connected to the second ion implantation area; forming a third ion implantation area by implanting second conductive-type ions into the third well on the second ion implantation area, so that the third ion implantation area is electrically connected to the second plug; and forming a first conductive-type ion implantation area on a portion of the third well electrically disconnected from the third ion implantation area by at least one of the isolation areas.