SI NANOSTRUCTURES FORMED BY PATTERN-DEPENDENT OXIDATION

A quantitative evaluation of the local Si thickness of oxidized Si nan ostructures was performed by scanning probe microscopy. Suppression of oxidation by mechanical stress is a dominant factor in determining th e shape of Si structures of widths <100 nm. Oxidation from below cause d by oxygen diffusion in the buried oxide layer extends to a few hundr ed nanometers from the pattern edge. The vertical position of the Si s tructure can be changed within a few tens of nanometers by oxidation f rom be:ow. As a result of co-occurence of these two phenomena, the loc al thickness of the patterned Si layer can be controlled within a rang e of 0-300% of the unpatterned area thickness.