Fabrication of Self-Aligned Nano-Structured Electron Emitters for Field Emission Scanning Electron Microscopy

Recent progress on aberration correction optics and single atom spectroscopy techniques increase needs of higher brightness electron sources than conventional single crystalline tungsten emitters. For this purpose, we are trying to fabricate a self-aligned nano-structured electron emitter using a field emission induced growth (FEIG) method in a field emission microscope (FEM) apparatus. The growth process can be monitored by the FEM, so that it is possible to control the nano-emitter size. A fabricated nano-emitter was mounted on a commercially available field-emission scanning electron microscope (FE-SEM) and its practicality was investigated. As compared with a carbon nanotube(CNT) emitter, the nano-emitter achieves larger beam current (better image contrast) and shows higher vibration durability. Emission stability of the nano-emitter is also within practical level, so that it was demonstrated that the FEIG nano-emitter could be a leading candidate for substituting conventional field emitters.