Nanolithography of silicon: An approach for investigating tip-surface interactions during writing

We report an approach for monitoring tip-surface interactions. The approach is based on power spectrum analysis of atomic force microscope (AFM) tip o scillations during scanning probe nanolithography on Si surfaces. A single mode harmonic oscillator model allows us to determine the main characterist ics of the AFM tip-surface interaction: the amplitude of oscillation, the r esonant frequency, and the damping factor, during the writing process. We m easure these quantities in scanning probe anodization versus the bias volta ge. By fixing the length of lithographically patterned lines, and the energ y deposited into each line, we search for trends which may reveal the major factors controlling the quality of AFM-written nanostructures. Our data ar e consistent with the concepts that a water meniscus and electrostatic tip- surface interactions dominate contact AFM lithography. (C) 2001 American In stitute of Physics.