Diffusion of Atomic Oxygen on the Si(100) Surface

TitleDiffusion of Atomic Oxygen on the Si(100) Surface
Publication TypeJournal Article
Year of Publication2010
AuthorsArora P, Li W, Piecuch P, Evans JW, Albao M, Gordon MS
Journal TitleJournal of Physical Chemistry C
Date Published7/29
ISBN Number1932-7447
Accession NumberISI:000280070900039
Keywordsbasis-set, chemical-vapor-deposition, elevated-temperatures, mm3 force-field, molecular-orbital methods, monte-carlo simulations, open-shell systems, plesset perturbation treatment, renormalized coupled-cluster, self-consistent-field

The processes of etching and diffusion of atomic oxygen on the reconstructed Si(100)-2 x 1 surface are investigated using an embedded cluster QM/MM (Quantum Mechanics/Molecular Mechanics) method, called SIMOMM (Surface Integrated Molecular Orbital Molecular Mechanics). Hopping of an oxygen atom along the silicon dimer rows on a Si15H16 cluster embedded in an Si136H92 MM cluster model is studied using the SIMOMM/UB3LYP (unrestricted density functional theory (UDFT) with the Becke three-parameter Lee Yang Parr (B3LYP) hybrid functional) approach, the Hay-Wadt effective core potential, and its associated double-zeta plus polarization basis set. The relative energies at stationary points on the diffusion potential energy surface were also, obtained with three coupled-cluster (CC) methods, including the canonical CC approach with singles, doubles, and noniterative quasi-perturbative triples (CCSD(T)), the canonical left-eigenstate completely renormalized (CR) analogue of CCSD(T), termed CR-CC(2,3), and the linear scaling variant of CR-CC(2,3) employing the cluster-in-molecule (CIM) local correlation ansatz, abbreviated as CIM-CR-CC(2,3). The pathway and energetics for the diffusion of oxygen from one dimer to another are presented, with the activation energy estimated to be 71.9 and 74.4 kcal/mol at the canonical CR-CC(2,3)/6-31G(d) and extrapolated, OM-based, canonical CR-CC(2,3)/6-311G(d) levels of theory, respectively. The canonical and CIM CR-CC(2,3)/6-31G(d) barrier heights (excluding zero point vibrational energy contributions) for the etching process are both 87.3 kcal/mol.

URL<Go to ISI>://000280070900039