Equipping a transmission electron microscope with a field emission electron gun.

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We investigated to apply carbon nano-tubes (CNT) to field emission electron guns for transmission electron microscopes (TEM). Fundamental tips of SiC are prepared by a precision diamond cutter and CNTs are grown by surface decomposition on the top (000-1) surface. The detail of the process is shown hereafter:1.A rod of SiC single crystal along <0001> orientation having a top surface of 0.5mmx0.5mm is cut out by the precise diamond sow with a blade of a special figure. 2.The strain introduced in the cutting process is removed by chemical etching and chemical washing. 3.Focused Ion Beam (FIB) processing are introduced to make the rod thinner. To avoid damaging the top surface, SiO_2, Al or Won Al was evaporated on the rods. 4.Removed the layer of SiO_2 or Al, the rods were heat-treated in a vacuum of 1Pa at 1700℃ for 6hours. The growth of CNTs was confirmed even on the top surface of 0.2μmx0.3μm. 5.In order to give a high conductivity to the tip, graphite layers were grown on a (1210) surface by a heat-treatment in the vacuum of 1x10^<-2>Pa at 1700℃ for 10hours.Field emission characteristics were measured in a high vacuum chamber less than 1x10^<-7>Pa and emission patterns were observed on a fluorescent screen.