Effects of film dimension on the phase transformation behavior of NiTi thin films

Huang, Xu; Ramirez, A. G.
September 2009
Applied Physics Letters;9/7/2009, Vol. 95 Issue 10, p101903
Academic Journal
This letter demonstrates the role of film geometry on the phase transformation and shape memory behaviors of NiTi thin films. Lithographically patterned lines possess a strain profile that significantly alters their phase transformation behavior and surface morphology in comparison to continuous films, although the microstructures remain the same. The stress profile causes the film curvature to change with direction: concave parallel to the line and convex when perpendicular. Additionally, patterned lines require higher temperature excursions for complete phase transformations; their transformation temperature interval doubled that of the continuous film. Such observations illuminate how microelectromechanical system embodiments of these materials may behave.


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