Patent ID: 8134212
Filing Date: 2012-03-13
Classification: H01L

Abstract:
1. An n-type isolation structure, comprising: an n-type buried isolation (BISO) layer overlapping a boundary between a p-type substrate and a p-type epitaxial layer, such that a top surface of said n-type BISO layer is lower than a top surface of said p-type epitaxial layer, and said n-type BISO layer is formed in a different area than an n-type buried layer (NBL); and a shallow n-well formed in said p-type epitaxial layer over said n-type BISO layer, extending from said top surface of said p-type epitaxial layer to, and overlapping a top surface of, said n-type BISO layer, wherein an average doping density in said shallow n-well is less than 10