Impact of guard ring layout on the stacked low-voltage PMOS for high-voltage ESD protection

Electrostatic discharge (ESD) protection and latchup prevention are two important reliability issues to the CMOS integrated circuits, especially in high-voltage (HV) applications. In this work, the stacked low-voltage (LV) PMOS devices have been successfully verified in a 0.5-μm HV process to provide high ESD level with high holding voltage for HV applications. In addition, the guard-ring layout on the stacked LV PMOS devices was further investigated in silicon chip to get high ESD robustness and latchup-free immunity for HV applications.