Patent ID: RE43215

Claim:
A semiconductor structure for electrostatic discharge (ESD) protection of a metal oxide semiconductor (MOS) integrated circuit , said semiconductor structure comprising: a substrate of a first conductivity type forming that forms a base for said semiconductor structure; a first region of a second conductivity type within said substrate for forming that forms a drain of a first MOS transistor; a second region of the second conductivity type within said substrate for forming that forms a source of the first MOS transistor; a third region of the second conductivity type within said substrate for forming that forms a source of a second MOS transistor, wherein and a fourth pick up diffusion region of the first conductivity type is disposed between the second region of said first MOS transistor and the third region of said second MOS transistor for between the second region of said first MOS transistor and the third region of said second MOS transistor, wherein the pick up diffusion region surrounding surrounds said first MOS transistor with an additional laterally, wherein said second MOS transistor is not included within the pick up diffusion region, wherein the pick up diffusion region is configured to restrain the a turn on of said first MOS transistor; and wherein the a channel length of said first MOS transistor is longer than the a channel length of said second MOS transistor to increase the a drain base voltage of said first MOS transistor.