Low-loss electron image in the sem

Abstract

The idea of filtering the backscattered electrons (BSE) in the scanning electron microscope (SEM) in order to improve the spatial resolution was suggested by McMullan (1953a) as follows: “...the beam from the specimen could be restricted to the electrons which have lost only small amounts of energy and which have therefore travelled only short distances through the specimen.” BSE which have lost less than about 1% of the primary energy can be called “low-loss electrons” or LLE (Wells 1971). As compared with LLE, the reflected electron peak contains electrons that have lost essentially no energy (Seiler 1983).Data on BSE and LLE from solid targets was given by Kanter (1957) and by Wolf, Coane and Everhart (1970). The wide-angle scintillator detector for BSE (in which the scintillator subtends a large solid angle at the specimen) was investigated by Smith (1956) and by Everhart (1958). The importance of the takeoff angle with this detector was shown experimentally by Wells (1957 and 1970).