Auger microscopy using sample modulation

Although the spatial resolution of a scanning Auger microprobe is limited by its electron optics, its effectiveness for the analysis of semiconductor devices that have features of interest comparable in size to the diameter of the analyzing electron beam is enhanced by a variation in the method of signal detection. Signal detection in an Auger spectrometer is most often accomplished using phase‐sensitive detection. The modulating signal required in the phase‐sensitive detection process is applied to the electron energy analyzer. Instead, by applying the modulating signal directly to different electrically isolatable regions of a device, only those Auger electrons originating in a particular region are detected. By rejecting signals from regions adjacent to a modulated region, Auger spectra characteristic only of the region of interest are obtained without spurious contributions from adjacent areas inadvertently illuminated by the analyzing beam.