MICROFABRICATION OF AFM TIPS USING FOCUSED ION AND ELECTRON-BEAM TECHNIQUES

Production of reproducible AFM tips with narrow and straight tip shanks is important for metrology and imaging of various submicron and high topography structures. Possibilities of micromachining commercial AFM pyramidal tips with focused ion beam (FIB) techniques have been investigated to improve the sharpness of the pyramidal tips. Also, the fabrication of electron-beam-induced microtips grown on the top of the pyramidal tips has been developed using a combination of focused ion and electron beam techniques. Microtips were reproducibly grown with tip shanks of 1.0-mu-m length and 0.1-mu-m diameter. The tip geometry was found to degrade only slightly after extensive AFM imaging, indicating minimal wear on the microtip during AFM scanning. The radius of curvature remained as sharp as 25 nm after tens of hours of AFM imaging in the contact mode. The microtips were found to be considerably stronger and more stable when they were grown on pyramids which had been heavily implanted with Ga ions.