Emission sensitivity to tip position of Spindt-type field emitters

The emission characteristics of the Spindt-type field emitter are investiga ted as a function of the tip position with respect to the gate. The tip pos ition is varied by either changing the hole diameter in the photomask or th e dielectric layer thickness. Under low anode field, the measured emission current is sensitive to the tip position and drops quickly as the tip rises above the middle of the gate, which is consistent with the computer simula tion result. Under high anode field, the computer simulation result shows t hat the emission increases for some distance above the gate electrode and t hen slowly falls off with increasing tip height. There is a "flat" region w hen emission is less sensitive to the tip position, The array with tall tip s shows better emission uniformity. Two different types of emission pattern s are observed for short and tall tips. The short tips show large blurry sp ots and the tall tips small sharp spots. (C) 2000 American Vacuum Society. [S0734-211X(00)01804-7].