ELECTROSTATIC DISCHARGE STRUCTURE OF SEMICONDUCTOR DEVICE

PROBLEM TO BE SOLVED: To avoid malfunctioning of an internal circuit by a method wherein an N-MOS transistor for electrostatic discharge is formed in a P-type pocket well isolated from a P-type semiconductor substrate. SOLUTION: An N-type source region 118 and an N-type drain region 122 by which a channel region is restricted are formed on the surface of the predetermined region of a P-type pocket well 113 to constitute an ESD structure. A gate electrode 120 is formed on an gate insulating film provided above the channel region between the source region 118 and the drain region 122. The drain region 122 is connected to an address pad 126 through a wiring 124. A P-type active guide line 116 is connected to a grounding terminal with the source region 118. The drain region 112 and the gate electrode 120 constitute an N-MOS transistor for ESD. With this constitution, the malfunctioning of a semiconductor device which is caused by the undershoot can be avoided.