The scanning tunneling microscope has been used to desorb hydrogen from hydrogen-terminated silicon (100) surfaces. As a result of control of the dose of incident electrons, a countable number of desorption sites can be created and the yield and cross section are thereby obtained. Two distinct desorption mechanisms are observed: (i) direct electronic excitation of the Si-H bond by field-emitted electrons and (ii) an atomic resolution mechanism that involves multiple-vibrational excitation by tunneling electrons at low applied voltages. This vibrational heating effect offers significant potential for controlling surface reactions involving adsorbed individual atoms and molecules.

Nanoscale patterning of the hydrogen terminated Si(100)-2×1 surface has been achieved with an ultrahigh vacuum scanning tunneling microscope. Patterning occurs when electrons field emitted from the probe locally desorb hydrogen, converting the surface into clean silicon. Linewidths of 1 nm on a 3 nm pitch are achieved by this technique. Local chemistry is also demonstrated by the selective oxidation of the patterned areas. During oxidation, the linewidth is preserved and the surrounding H-passivated regions remain unaffected, indicating the potential use of this technique in multistep lithography processes.

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Norbornadiene (bicyclo[2.2.1]Hepta-2,5-diene) is shown to chemisorb selectivity at room temperature onto clean Si(100)-2×1 surfaces. Combining the chemoselectivity of this process with scanning tunneling microscope nanolithography allows the formation of nanometer-sized regions having a norbonadiene adlayer. This concept could serve as the basis for creating spatially resolved templates to initiate chemical reactions with other chemical species in the presence of hydrogen-passivated Si(100)-2×1 areas.