Several lithographic techniques are used for patterning in the nanoscale region. The technique of Scanning Probe Lithography (SPL) uses the scanning tunneling microscope (STM) to produce nanometer-scale features on a sample.
Scanning Probe Microscope Lithography (SPM)
Scanning Probe Microscope Lithography (SPM) uses the tip of a scanning probe microscope to create a pattern. At its crudest, the tip can be used to produce marks by scratching, nanoindentation or by heating with the tip. A more elegant method uses the tip to oxidise material in a specific pattern. When a voltage is applied between the sharp probe tip and sample surface, an intense electric field is created that can be used to oxidise material in the vicinity of the tip. The oxidised material can then be removed by preferential etching.
Some researchers have been able to use SPM to produce features with a resolution as low as around 10nm. Even smaller resolutions may be possible as the scanning microscope can be used to manipulate individual atoms.
It is envisaged that SPM lithography may be used to produce future generations of computer chips and electrical devices.