Microfabricated small metal cantilevers with silicon tip for atomic force microscopy

Abstract

Atomic force microscopy with small cantilevers is faster due to higher resonant frequencies and has a lower noise level. We report a new process to microfabricate small metal cantilevers with integrated silicon tips. This process is used to fabricate gold cantilevers that are 13-40-/spl mu/m long, 5-10-/spl mu/m wide, and 100-160-nm thick. The tip is first formed at the free end of a sacrificial oxide cantilever. The cantilever layer of the desired metal is then deposited on the nontip side of the sacrificial oxide cantilever. The oxide layer is removed to form the cantilevers with tips on them in a batch process. The highly stressed cantilevers are rapid thermal annealed for 60 s at 300/spl deg/C to relieve the stress. The gold cantilevers have been characterized through their thermal spectra and used to image in tapping mode. The process can be used, not only for gold, but also for any metal or compound that can withstand removal of sacrificial oxide cantilevers.