The hetero-epitaxial strain relaxation in nano-scale systems plays a fundamental role in shaping their properties. Here, the elastic and plastic relaxation of self-assembled SiGe islands grown by surface-thermal-diffusion from a local Ge solid source on Si(100) are studied by atomic force and transmission electron microscopies, enabling the simultaneous investigation of the strain relaxation in different dynamical regimes. Islands grown by this technique remain dislocation-free and preserve a structural coherence with the substrate for a base width as large as 350 nm. The results indicate that a delay of the plastic relaxation is promoted by an enhanced Si-Ge intermixing, induced by the surface-thermal-diffusion, which takes place already in the SiGe overlayer before the formation of a critical nucleus. The local entropy of mixing dominates, leading the system toward a thermodynamic equilibrium, where non-dislocated, shallow islands with a low residual stress are energetically stable. These findings elucidate the role of the interface dynamics in modulating the lattice distortion at the nano-scale, and highlight the potential use of our growth strategy to create composition and strain-controlled nano-structures for new-generation devices.

Vanacore, G., Nicotra, G., Zani, M., Bollani, M., Bonera, E., Montalenti, F., et al. (2015). Delayed plastic relaxation limit in SiGe islands grown by Ge diffusion from a local source. JOURNAL OF APPLIED PHYSICS, 117(10), 104309 [10.1063/1.4914409].

Delayed plastic relaxation limit in SiGe islands grown by Ge diffusion from a local source

Vanacore, G;BONERA, EMILIANO;MONTALENTI, FRANCESCO CIMBRO MATTIA;
2015

Abstract

The hetero-epitaxial strain relaxation in nano-scale systems plays a fundamental role in shaping their properties. Here, the elastic and plastic relaxation of self-assembled SiGe islands grown by surface-thermal-diffusion from a local Ge solid source on Si(100) are studied by atomic force and transmission electron microscopies, enabling the simultaneous investigation of the strain relaxation in different dynamical regimes. Islands grown by this technique remain dislocation-free and preserve a structural coherence with the substrate for a base width as large as 350 nm. The results indicate that a delay of the plastic relaxation is promoted by an enhanced Si-Ge intermixing, induced by the surface-thermal-diffusion, which takes place already in the SiGe overlayer before the formation of a critical nucleus. The local entropy of mixing dominates, leading the system toward a thermodynamic equilibrium, where non-dislocated, shallow islands with a low residual stress are energetically stable. These findings elucidate the role of the interface dynamics in modulating the lattice distortion at the nano-scale, and highlight the potential use of our growth strategy to create composition and strain-controlled nano-structures for new-generation devices.
Articolo in rivista - Articolo scientifico
Heteroepitaxy; Semiconductors
English
2015
117
10
104309
104309
none
Vanacore, G., Nicotra, G., Zani, M., Bollani, M., Bonera, E., Montalenti, F., et al. (2015). Delayed plastic relaxation limit in SiGe islands grown by Ge diffusion from a local source. JOURNAL OF APPLIED PHYSICS, 117(10), 104309 [10.1063/1.4914409].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/83320
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