Electron-induced H atom desorption patterns created with a scanning tunneling microscope: Implications for controlled atomic-scale patterning on H-Si(1 0 0)

We have used scanning tunneling microscopy (STM) to explore the details of single and multiple H atom desorption from the H-Si(1 0 0)-2 × 1 surface induced by the inelastic scattering of electrons from an STM tip. The desorption of pairs of H atoms from individual Si dimers is rarely observed. Two-H atom desorption most often involves pairs of dimers, in the same or adjacent rows. This suggests that recombinative H2 desorption via an interdimer reaction pathway, like that observed recently under nanosecond laser heating, may also be operative for electron-induced excitation using STM. Repeatable fabrication of desired size-selected dangling bond (DB) clusters is also achieved. The single atomic precision of the fabrication is a result of the intrinsically unfavorable paired H atom desorption from a single dimer, but does not result from the spatial localization of excitation energy of the Si-H bond under the STM tip as suggested in previous studies.