Patent ID: 6624487
Filing Date: 2003-09-23
Classification: H01L

Abstract:
A structure for the protection of functional circuitry from electrostatic discharge at a terminal, comprising:a pump transistor disposed at a semiconducting surface of a substrate of a first conductivity type, comprising: a drain region of a second conductivity type, connected to the terminal and disposed within a well region of the second conductivity type at the surface; a gate electrode, overlapping a portion of the well region within which the drain region is disposed, and insulated from a channel region by a gate dielectric, the channel region being of the first conductivity type; and a source region, disposed at the surface adjacent to the channel region; a protection transistor disposed at the surface of the substrate, comprising: a drain region connected to the drain region of the pump transistor; a source region; and a gate electrode connected to the gate electrode of the pump transistor and insulatively disposed over a channel region of the substrate located between the source region and the drain region; and a guard ring of the first conductivity type surrounding the protection transistor, and connected to the source region of the pump transistor.