Persistent Laser-Induced Leakage in a 20 nm Charge-Pump Phase-Locked Loop (PLL)

A persistent loss-of-lock error was experimentally observed in a 20 nm charge-pump phase-locked loop (PLL). Through circuit modeling and simulation, the observed error was attributed to a non-recoverable off-state leakage increase resulted from two-photon absorption (TPA) laser-induced damage. The laser-induced damage is consistent with results from 28 nm bulk transistors.