Si-adatom dynamics and mechanisms of the epitaxial growth on a single-height-stepped Si{001} surface

Deepak Srivastava, Barbara J. Garrison

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43 Scopus citations

Abstract

The Si-adatom dynamics on a single-height-stepped Si{001} surface is studied via a combined molecular-dynamics, simplified transition-state theory and time-dependent lattice-gas description using Tersoff's potential for Si-Si interactions. The energies of adatom binding and migration near SA, SB(b) (bonded), and SB(n) (nonbonded) step edges show that the global minima, 4.28 eV, are in the trenches at the SB(n) edges. At all other sites, the binding energies are comparable to those on the flat Si{001}-(2×1) surface. We find that if the adatoms are deposited on an SB terrace, reflection dominates at the SA edge, whereas at the SB(b) and SB(n) edges, adatoms step down and migrate in the trenches parallel to the edges. The deposition rate and surface-temperature-dependent reflection, step up, step down, and accommodation probabilities at all three step edges are calculated and used in a simple estimation of step-edge growth coefficients. We find that the allowable surface-temperature range in which a 400-Å-wide SB terrace may grow at the SB(b) and SB(n) edges is above 800 K for the 0.30 ML/min (where ML denotes monolayer) film deposition rate and above 700 K for the slower 0.03 ML/min film deposition rate. A microscopic model of the growth of SB terraces is also presented in which we find that the nature of the growth, by accommodation, at the SB(b) and SB(n) edges, is different such that it maintains the roughness of the growing edge of an SB terrace.

Original languageEnglish (US)
Pages (from-to)4464-4474
Number of pages11
JournalPhysical Review B
Volume47
Issue number8
DOIs
StatePublished - 1993

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

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