AFM Anodic Oxidation Lithography is a kind of the
AFM Voltage Lithography. With the help of the Voltage Lithography not
only geometrical properties of the surface but also the local
electrophysical properties of the sample surface can be changed. For
example, by application of voltage to conductive cantilever the
electrochemical processes on the surface can be stimulated under the
probe tip and metalic layer can be oxidased.
Particularly
tip-induced oxidation of the surface of hyperfine titanium film on the
silicon substrate under normal conditions is demonstrated on the
animated picture [1].
In air or other humid atmosphere the probe and the surface of the
sample are covered by thin film of absorbed water. When the tip
approaches sufficiently close to the surface, these absorbed layers
come in contact and water bridge is produced because of capillary
effect. With application of a corresponding electric field the
electrochemical reaction in water-surface border, in water and in the
probe will be initiated through that bridge. If the surface is
positively charged and the tip negatively, then the tip and the surface
will interact electrochemically as anode and cathode correspondingly.
Oxide will grow on the point right under the tip.
For complex pictures Raster Lithography can be execute by using PCX-file [2].
Difference between minimum and maximum tone voltage will be applied
proportionally to brightness and, correspondingly, anode oxide will
grow to a different height forming different contrast of topographical
image.
References
Nanotechnology 12, 273 (2001).
"1st euspen topical conference on fabrication and metrology in nanotechnology". -Copenhagen, 2000. V.1, р.222-228.
