Noncontact High-Speed Waveform Measurements with the Picosecond Photoelectron Scanning Electron Microscope

We have replaced the electron gun and beam blanking system of a conventional voltage contrast scanning electron microscope by a pulsed laser/photocathode combination, resulting in a source pro-ducing electron pulses of order 1 ps in duration at a 100 MHz repetition rate and with a peak brightness of 3 108 A/cm2 sr at 1.8 keV. This novel instrument has demonstrated stroboscopic noncontact waveform measurements on metal interconnect lines in different environments with a temporal resolution better than 5 ps, a voltage resolution of 3 mV/(Hz)1/2, and a spatial resolution of 0.1 μ m. These measurements are achieved with extraction fields above the sample of about 1 kV/mm. © 1988 IEEE