Low Voltage Scanning Electron Microscopy (LVSEM) in Perspective

Abstract In the past quarter century low voltage SEM (LVSEM) has been developed for use in a wide range of applications, and it has become the main area of innovation in SEM, and now perhaps more widely in electron microscopy. The intellectual challenge (1,2) has been transformed into a vital tool of modern technology in the semiconductor, polymer and chemical industries, and is widely used in the materials and biological sciences (3, 4). It has been claimed by this author and others that LVSEM is the rational and preferred state of SEM, but unfortunately at the time of the first SEMs only higher voltage systems could be built with the technologies available half a century ago (1). The primary advantage of the SEM remains the use of real bulk specimens with a minimum of potentially invasive preparation. A wide area in the range of square mms to sq inches can contain aperiodic, or otherwise infrequent, events in or on the surface, or in a simple snapped cross-section, and always using relatively stable bulk samples.