Scanning Microscopy


Tungsten emitter tips are observed with a prototype scanning electron microscope with an approximate SA electron beam size at an accelerating voltage of 30kV. A field emission electron source and in-lens type objective lens are incorporated into the electron column. A special specimen stage was designed to clean the emitter tips using a flashing operation and to reduce contamination by heating them during the observation. The observed emitters were W< 011 >, W< 001 > and Ti/W< 001 >. The crystallographic planes were clearly visible in the W< 011 > and W< 001 > observation. It was also possible to observe atomic layer steps of 4.5A during the recrystallization process by flashing operation of W< 011 >. In the observation of Ti/W, it was found that the aspect was quite different from that of the W< 001 > crystal surface. The observed field emission micrograph pattern was in good agreement with the tip shape.

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