Role of fast sputtered particles during sputter deposition: Growth of epitaxialGe0.99C0.01/Ge(001)

Abstract

We show that fast sputtered particles in the sputter-deposition process, largely ignored in previous studies, can play a major role in determining defect densities in as-deposited layers. Epitaxial Ge{sub 1-y}C{sub y}/Ge(001), in which there is a direct correlation between C lattice configurations and the local concentration of Ge self-interstitials, is used as a model materials system. We show that increasing the fraction of fast Ge neutrals in the high-energy tail of the ejected particle distribution increases the concentration of Ge--C split interstitials and thus the film compressive strain. The Ge--C split interstitials form as a result of trapping, by incorporated substitutional C atoms, of Ge self-interstitials produced by incident hyperthermal Ge atoms. Experimental results are supported by Monte Carlo simulations and ab initio calculations.