An Atomically-Resolved STM Study of the Interaction of Phosphine (PH3) with the Silicon (001) Surface
Interim rept. 1 Jun 1993-31 May 1994
WISCONSIN UNIV-MADISON DEPT OF CHEMISTRY
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The interaction of phosphine PH3 with the Si001 surface has been investigated with scanning tunneling microscopy. At 300 K, PH3 adsorbs molecularly on top of a single SiSi dimer with the phosphorus atom in a pentacoordinate configuration. Phosphine adsorption is accompanied by occasional ejection of silicon atoms from the substrate onto the surface, creating surface vacancies and Si adatoms. Si atoms are preferentially ejected from defect sites. At high coverage, adsorbed PH3 molecules order into small regions of c4x2 symmetry and the ejected silicon nucleates into small dimer strings. The long- range order of the molecular PH 3 is disrupted by domain boundaries and the ejected silicon. Annealing PH 3- saturated surfaces produces further ejection of silicon onto the surface, resulting in large silicon islands covering approximately 20 of the surface.
- Inorganic Chemistry
- Physical Chemistry
- Atomic and Molecular Physics and Spectroscopy