Mo field emitters with a lateral wedge have been fabricated using a dual beam system consisting of a focused ion beam (FIB) and a field emission electron beam. A FIB process was applied to the fabrication of a lateral-type wedge field emitter. An emitter-collector gap for the wedge emitter gap produced by physical sputtering of the Mo layer on SiO2/Si by a FIB and subsequent wet etching of the underlying silicon dioxide layer. Controlled gaps of 10-500 nm could be obtained by raster scanning of a FIB. An emission current of up to 2 muA was observed for a wedge emitter with a gap of 100 nm.