Patent ID: 6355508
Filing Date: 2002-03-12
Classification: H01L

Abstract:
A method of forming a protection device, comprising:forming an outer pad ring of a first conductivity at a first concentration in a substrate of a second conductivity; forming an inner pad ring of the first conductivity at a second concentration into the substrate within the outer pad ring, the second concentration higher than the first concentration, the inner pad ring abutting the substrate of a second conductivity; forming a rail contact of the first conductivity at a third concentration in the substrate; the rail contact being formed by forming an outer rail ring of the first conductivity at the third concentration in the substrate and forming an inner rail ring of the first conductivity at a fourth concentration in the substrate within the outer rail ring, the fourth concentration higher than the third concentration, the inner rail ring abutting the substrate of a second conductivity; forming a separation structure in the substrate between the outer pad ring and the outer rail ring; coupling the inner pad ring to a first portion of the device; and coupling the rail contact to a second portion of the device.