A full-process damage detection method using small MOSFET and protection diode

Short constant voltage stress was applied to the gate of triple metal process transistors to uncover otherwise undetectable process-induced damage, 1 s at 9 MV/cm was enough to distinguish the damaged devices from the undamaged ones clearly in the transistor characteristics. The process damage was detected even after forming gas anneal and without using large antenna test structures to gather the charges. Also, the small diode provided a good leakage path to protect the gate from plasma process induced charging even in the reverse polarity. Diode-protected devices can be used as references in this damage detection scheme.