Focused ion beam processing of metal gated field emitter arrays

Gate opening of metal layers in a field emitter array(FEA) was produced by physical sputtering using a focused ion beam (FIB) and subsequent wet etching of underlying silicon dioxide layer. Platinum tips were deposited into the gate opening using electron beam induced chemical reaction. Beam damage due to the FIB processing resulted in the enlargement of the gate diameter, After wet etching, the gate opening in Nb gated FEA was enlarged, while the smaller gate opening in Au gated FEA was easily fabricated because of the suppression of the enhanced etching. The gate opening could be controlled by selection of the gate metal materials. The turn-on voltage for field emission could be reduced by decreasing the diameter of the gate opening.