Microprotuberance Processing of Silicon by Diamond Tip Scanning

In this study, the properties and mechanism of Si microprotuberance processing are evaluated with diamond tip scanning using atomic force microscopy (AFM) in the atmosphere. Microprotuberances on the surface approximately 1-nm-high were formed by mechanochemical action. To control the height of the processed microprotuberances, the height dependencies on load, scanning cycles and scanning area were studied. To clarify the mechanism of mechanochemical action, the contact stress was analyzed by the boundary element method. The following results were obtained:(1) A diamond tip with nearly 100 nm radius sliding produced an approximately 1-nm-high microprotuberance on the Si surface. (2) Processed microprotuberance height increased with applied load. Microprotuberance and microsinkage were produced by sequential scanning and a profile similar to a sine curve was formed after four scannings. (3) To clarify the swelling mechanism, surface contact stress was evaluated. Oxidation and hydroxidation were speculated to occur at the rear edge of the sliding contact area at which the elongation stress is the maximum. (4) To produce the three-dimensional microprofile, the processed profile dependence on scanning area was evaluated, and then 3-nm-high micropyramids were formed as an application of this processing.