Isolating marginally defective gate using photoperturbation induced via a C-AFM laser beam

The photoperturbation effects induced via a Conductive Atomic Force Microscope (C-AFM) laser beam, in which the surface photovoltaic effect and the carrier injection effect included in the photoperturbation can cause significant deterioration in the characterization accuracy have been widely investigated. This study, however, successfully demonstrates how to take advantage of these non-negligible photoelectric effects to isolate marginally defective gates, which are usually difficult to uncover using the traditional approach of passive voltage contrast (PVC) carried out using a scanning electron microscope (SEM) or focused ion beam (FIB), or even when using an advanced SEM-based nanoprobing technique. Using this technique, such failures, which pose potential reliability issues on devices as the affected circuit degrades over time or under stress, can be easily screened before any quality assurance test.