Characterization of dynamic spatial conduction patterns on ESD protection circuitry by photon-counting imaging

A photon-counting imaging method has been effectively employed to acquire the extremely weak pulse electroluminescence from a thick-field-oxide electrostatic discharge (ESD) protection device during very short pulse stressing. From this, its dynamic spatial conduction patterns with respect to different currents, pulse widths, and repetition rates could then be directly visualized and assessed. The authors have applied such an imaging method successfully in the acquisition of a full series of spatial pulsed emission patterns on circuitry during ESD simulation. This could offer a means for direct, simultaneous observation of emerging failure on such a device. The exact sequential turning-on nature of bipolar NPN snapback, on each ladder-channel and its non-uniformity in spread during different levels and widths of pulsation could also be resolved directly. The authors report on the accurate determination of the site of the resistive short on failed samples by this technique.<>