Secondary electron spectrometer for measuring voltages on a sample utilizing an electron probe

Claim 1

A secondary electron spectrometer for detecting the energy distribution of secondary electrons from a measuring point on a sample independent of the angular distribution of said secondary electrons, said spectrometer inclucing an electron detector and comprising in sequence between said sample and said detector; an extraction electrode generating an extraction field for accelerating said secondary electrons from said sample; a deceleration electrode generating a deceleration field for decelerating said secondary electrons after passing through said extraction field; a hemispherically symmetrical electrode generating another deceleration field for further decelerating said secondary electrons, said hemispherically symmetrical electrode isotropically decelerating said secondary electrons; and an acceleration electrode generating another extraction field for accelerating said secondary electrons toward said detector.