A Split Island Layout Style of Butting/Inserted Substrate Pickups for NMOSFET ESD Reliability

Abstract

Butting/inserted pickup layout style could result in severe ESD degradation of NMOS devices beyond deep submicron technology. A split island layout style of butting/inserted substrate pickups is designed for a multifinger NMOS structure to enhance its ESD reliability. This layout style divides the substrate pickup diffusion bands along the whole polygate finger direction into segmented diffusion islands in the source area. This layout technique could improve the TLP second breakdown current of the 1.8 V butting pickup structure by 58~66% and 1.8 V/3.3 V inserted pickup case by 2.8 times. This style also shows excellent enhancement for the ESD/HBM levels of the 1.8 V and 3.3 V butting pickup case by 2.1~2.3 times and 18%~6 times, respectively, and the 1.8 V and 3.3 V inserted pickup case by 2.4~2.9 times and 13%~6 times, respectively. This simple technique could restore the ESD threshold level of the butting/inserted pickup layout style back to that of the normal GGNMOS without any further area consumption or fabrication cost.