Description:
A nanometer-scale mask that can be used for selective growth or selective etching was obtained by two-stage patterning. In the first step, a microscopic patterning was performed using a scanning electron microscope (SEM). In the SEM the mask was deposited by decomposition of residual oil molecules in the vicinity of the semiconductor surface. In the second stage, patterning of the carbonaceous film was made using an atomic force microscope (AFM). Use of the AFM assures not only a precise alignment with the previous marks but also a better resolution. Applying an electric bias between the conductive tip and the substrate surface previously covered with the carbonaceous film gave the local modification of the film composition. Further etching resulted in the pattern formation on the semiconductor surface with a minimum linewidth of ∼22 nm.