FABRICATION OF 0.4-MU-UM GRID APERTURES FOR FIELD-EMISSION ARRAY CATHODES

Field emitter array cathodes with 0.4 mum aperture diameter in the ext raction gate layer have been fabricated and successfully tested. These devices require a fabrication technique which delivers an ultimate un iformity of the apertures in the gate layer. Optical 5:1 lithography w ith a g-line stepper (NA=0.33) was available to fulfill the task. By t his technique the resolution is limited to about 1 mum. In order to fu rther reduce the aperture diameter to 0.4 mum a spacer technique in co mbination with Reactive Ion Etching (RIE) was developed and is discuss ed in detail. The field emission tips were fabricated using a self-ali gning evaporation technique. An onset of field emission (on the averag e 10 nA/tip) was observed at an extraction voltage of about 30 V. Arra ys of 100 tips covering an area of 25 mum x 25 mum can deliver electro n currents of 2 mA at 68 V gate voltage.