Silicon Backbond Strain Effects on NH3 Surface Chemistry - Si(111)-(7x7) Compared to Si(100)-(2x1)
Abstract
The role of surface structure in controlling NH3 surface chemistry has been investigated by HREELS and TPD on Si(lll)-(7x7) and Si(100)-(2xl). Following the initial NH3 dissociative adsorption producing NH2(a) and H(a), the production of >NH(a) species iS favored on Si(lll)-(7x7) between 300-600 K. This is believed to occur through the insertion of >NH(a) into the backbond of the Si adatom on Si(111)-(7x7) and to be driven by the relief of bond strain on the Si adatom backbonds. By contrast, this stepwise reaction mechanism is absent on Si(1001-(2xl). Instead, the surface NH2(a) species remain thermally stable until -600 K, when a new reaction channel opens up leading to the partial depletion of NH2(a) by recombination with H(a) to form NH3(g).
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 11, 1992
- Accession Number
- ADA248297
Entities
People
- J. T. Yates Jr.
- M. L. Colaianni
- P. J. Chen
Organizations
- University of Pittsburgh