Field emission cathodes have been examined to be applied to electron beam s
ystems such as electron microscopes and electron beam exposure systems. The
most important factors for such cathodes are brightness and stability. Fie
ld emission cathodes are very bright, but the electron emission fluctuates
greatly. Materials for the field emission cathode should be examined system
atically with a view towards stable emission. Nitride needles of transition
metals of Nb are obtained by heating elemental metal needles in an ammonia
gas atmosphere. The NbN needle gave the most stable field emission current
among the niobium nitrides examined here. (C) 1999 Elsevier Science B.V. A
ll rights reserved.