Patent ID: 7238553
Filing Date: 2007-07-03
Classification: H01L

Abstract:
1. A method of forming a silicon controlled rectifier, the rectifier having a substrate, an epitaxial layer of a first conductivity type formed on the substrate, a first semiconductor region of the second conductivity type formed in the epitaxial layer, and a second semiconductor region of the first conductivity type formed in the epitaxial layer, the epitaxial layer having a top surface, the first and second semiconductor regions contacting the top surface of the epitaxial layer, the method comprising: forming a layer of polysilicon that contacts the top surface of the epitaxial layer; and doping and etching the layer of polysilicon to form a first polysilicon region over the first semiconductor region, a second polysilicon region over the first semiconductor region, and a third polysilicon region over the second semiconductor region.