Noncontact high-speed waveform measurements with the picosecond photoelectron scanning electron microscope

The authors have replaced the electron gun and beam blanking system of a conventional voltage contrast scanning electron microscope by a pulse-laser/photocathode combination, resulting in a source producing electron pulses of order 1 ps in duration at a 100 MHz repetition rate and with a peak brightness of 3 10/sup 8/ A/cm/sup 2/ 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 between than 5 ps, a voltage resolution of 3 mV/(Hz)/sup 1/2/, and a spatial resolution of 0.1 mu m. These measurements are achieved with extraction fields above the sample of about 1 kV/mm.<>