Molecular dynamics simulation of delamination of a stiff, body-centered-cubic crystalline film from a compliant Si substrate

L. M. Hale, X. W. Zhou, J. A. Zimmerman, N. R. Moody, R. Ballarini, W. W. Gerberich

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Compliant substrate technology offers an effective approach to grow high-quality multilayered films, of importance to microelectronics and microelectromechanical systems devices. By using a thin, soft substrate to relieve the mismatch strain of an epitaxial film, the critical thickness of misfit dislocation formation in the overlayer is effectively increased. Experiments have indicated that stiff films deposited onto Si substrates can delaminate at the interface. However, the atomic mechanisms of the deformation and the fracture of the films have not been well studied. Here, we have applied molecular dynamics simulations to study the delamination of a stiff body-centered-cubic crystalline film from a compliant Si substrate due to tensile loading. The observed mechanical behavior is shown to be relatively independent of small changes in temperature, loading rate, and system size. Fracture occurs at the interface between the two materials resulting in nearly atomically clean surfaces. Dislocations are seen to nucleate in the body-centered-cubic film prior to delamination. At higher strains, a phase change to a face centered cubic is observed within the body-centered-cubic film, facilitating extensive dislocation growth and interaction. The various defects that form prior to fracture are discussed and related to the mechanical properties of the system.

Original languageEnglish (US)
Article number083503
JournalJournal of Applied Physics
Volume106
Issue number8
DOIs
StatePublished - Nov 10 2009

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