REPAIR OF A LIQUID-METAL ION EMITTER BY A LIQUID-METAL ION EMITTER

Liquid metal ion source (LMIS) indium emitters which have been poisoned by contamination with backsputtered material were successfully repaired by sputtering off the contamination layer, using a focused indium ion beam from an indium LMIS. It is essential that the repair beam consists of In ions to prevent the emitters from getting poisoned by the repair process itself. Poisoned emitters have excessively high firing voltages, but usually normal operating voltages. Following repair, firing voltage and operating voltage differed by not more than 150 V. Repairs worked equally well if the indium film on the emitter to be repaired was cold or hot (molten). Repairs were performed on fully assembled emitter modules where the emitter tip was recessed behind a stack of beam forming electrodes. Repair times are of the order of 10-15 min.