Effect of Interstitials Embedded in Pre-Patterned Si Substrate on Location of Ge Nanoislands

Large-area periodical pattern on Si(100) was fabricated using combination of nanoimprint lithography and ion irradiation through mask. Ordered structures with grooves and ridges were prepared by the selective etching of regions amorphized by ion irradiation. Laterally ordered chains of Ge nanoislands were grown by molecular beam epitaxy of Ge on the pre-patterned Si substrates. It was shown, that the location of subsequently grown Ge nanoislands depends upon the sidewall inclination in grooves. The effect is ascribed to strain induced by Ge interstitials under the groove's bottom. Our proposal was confirmed by molecular dynamics calculations that allowed the determination of strain in grooves as dependent on the groove's shape.