Switching Time Extraction of CMOS Gates using Time-Resolved Emission (TRE)

The picosecond imaging for circuit analysis (PICA) technique, based on the collection of near-infrared (NIR) light emitted by hot-carriers in the transistor channel, has shown to be an invaluable method for measuring timing information and detecting faults in modern VLSI circuits. The optical waveforms obtained with this technique allow measuring propagation delays, signal skews and other time-dependent information in a non-invasive and very effective way. In this paper, we present an innovative methodology, with experimental confirmation, for extracting the switching time (slew rate) of a gate by means of time-resolved optical measurements (using PICA) and optical simulations based on a luminescence model in a SPICE simulator. The method represents a valuable extension of the set of PICA measurements for both circuit testing and improving hardware-model correlation, and thus process yield and reliability