| A new photocathode technology suitable for use in VLSI electron beam instruments such as lithography tools, microscopes, and surface characterization tools has been developed, characterized, and implemented in an electron beam column. The photocathode consists of a degenerately doped p;A prototype electron gun was constructed and installed on an ultrahigh vacuum Auger electron beam column. The electron optical brightness of the cathode is superior to that of tungsten or lanthanum hexaboride. Short laser pulses from a mode locked dye laser system were used to produce electron pulses directly from the cathode into vacuum, eliminating the need for high speed electron beam blankers and electronics when performing time domain metrology upon integrated circuits. A temporal resolution of 50 ps was obtained at a repetition rate of 82 MHz.;Fundamental cathode parameters were investigated such as noise, stability, emission uniformity, angular distribution, cathode operating temperature, and electron energy distribution. The cathode was found to have emission properties which make it suitable for a variety of VLSI electron beam applications, such as electron beam lithography, scanning electron beam microscopy, scanning Auger electron microscopy, and high speed time domain electron beam metrology. |
