Morphology control and integration of the carbon nanotube tip for AFM

We report the development of atomic force microscope (AFM) tip with a carbon nanotube (CNT). To assemble the CNT on the top of Si tip, we used dielectrophoresis (DEP) which is caused by the difference of the polarizability of a CNT and a medium under a non-uniform electric field. We investigated the effect of the assembling angle between the tip and the flat electrode. As the result, it was found that the angle orientation and the fabrication yield of the CNT tip depended on this assembling angle. The assembling angle condition for highest success rate was 10° in tip's angle and 20° in electrode's angle. In addition, to make the CNT tip that slants vertically, we developed the new technique by the focused-ion-beam (FIB). The directionality of the CNT was changed according to the beam direction of FIB. Moreover, the straightness of the CNT was greatly improved by the ion beam. From the AFM measurements of 15 nm gold particles, we showed that the CNT tip assembled by DEP produces higher resolution images than those of a conventional silicon tip.