Tools for contactless testing and simulation of CMOS circuits

Short channel effects in MOSFETs are responsible for time-dependent hot-car rier luminescence, synchronous with the switching transitions in CMOS circu its. We propose an optical non-invasive inspection technique for high-speed signals, based on a high sensitivity solid-state photodetector with sharp time resolution. This tool is able to probe the fast electrical waveforms p ropagating through ULSI circuits without electrically loading the circuit u nder test. The measured time resolution of 50 ps allows an equivalent analo g bandwidth of about 20 GHz. From the experimental results and the luminesc ence characterization of single transistors, we propose a SPICE model able to foresee the photoemission in complex ULSI circuits, down to transistor l evel. The optical testing equipment and the SPICE modeling are valuable too ls for simulation, characterization and testing of fast ULSI circuits. (C) 2001 Elsevier Science Ltd. All rights reserved.