ENERGY OF SI(111) DIMER-STACKING-FAULT STRUCTURES

In this work we show that the relative formation energies of stacking faults, dimer rows, and rebonded corner holes can be determined by ana lyzing the size distribution of dimer-stacking-fault (DS) structures t hat are found along extended (11 (2) over bar) step lengths of the Br- passivated Si(11)-1 x 1 surface. Using this method we report an energy of 1.75 eV for the rebonded corner holes associated with these DS str uctures. These energies are in turn used to predict the partitioning o f DS structures along short [11 (2) over bar] step lengths, yielding r esults that are in good agreement with experiment. We also introduce a model that describes DS structures as an ordered collection of vacanc ies subject to the topological bonding constraints of the Si diamond l attice. In this manner, we establish that there is a thermodynamic dri ving force for the coalescence and formation of large isolated DS stru ctures on adsorbate-stabilized Si(111)-1x1 terraces. This result has i mportant implications for the feasibility of forming defect-free bulk- terminated Si(111) surfaces by exposure of the Si(111)-7 x 7 surface t o hydrogen or halogens. [S0163-1829(98)05715-4].