Chips at Work: Picosecond Imaging Circuit Analysis

Abstract

Picosecond pulses of hot electron luminescence are observed from individual submicron FETs in CMOS circuits. The pulses are synchronous with logic state switching. We have developed a method to simultaneously image and time resolve this weak emission. The emission has been used to measure AC operation of integrated circuits from a simple ring oscillator to a full microprocessor. Examples of circuit characterization and fault diagnosis are presented.