Mechanical stresses upon crystallization in phase change materials
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Date
2001
Authors
Njoroge, W. K.
Kalb, J.
Wamwangi, D.
Wuttig, M.
Spaepen, F.
Journal Title
Journal ISSN
Volume Title
Publisher
American Institute of Physics
Abstract
Crystallization processes in different Te alloys, employed in phase change materials for optical data storage, have been investigated by in situ mechanical stress measurements. Upon crystallization a considerable stress buildup is observed, which scales with the volume change upon crystallization. Nevertheless the observed stress change only corresponds to approximately 9% of the stress estimated for a purely elastic transformation. Further evidence of stress relief phenomena comes from the temperature dependence of the stress in the crystalline and amorphous states. Ultrathin dielectric layers have a profound influence on the crystallization process as evidenced by simultaneous optical reflectance and mechanical stress measurements. This observation can be explained by heterogeneous nucleation of crystallites at the interface between the dielectric layer and the phase change film.
Description
http://dx.doi.org/10.1063/1.1415419
Keywords
crystallisation, optical storage, solid-state phase transformations, stress measurement, tellurium alloys
Citation
Applied Physics Letters 79 , 3597 (2001)