Stress Generation and Relaxation in Thin Films: The Role of Kinetics and Grain Boundaries

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Stress Generation and Relaxation in Thin Films: The Role of Kinetics and Grain Boundaries
Shin, Jae Wook (creator)
Chason, Eric (director)
Bower, Allan (reader)
Gao, Huajian (reader)
Brown University. Division of Engineering. Materials Science Engineering (sponsor)
Copyright Date
In order to understand the stress behaviors in thin films, three related topics were investigated. First, intrinsic stress generation mechanisms were studied by in-situ stress measurements using a multi-beam optical stress sensor (MOSS) system during the electrodeposition of Sn films. The mobility of Sn is much higher than that of other materials which were used for the previous studies of intrinsic stress generation, so the stress behaviors here showed a more pronounced effect due to increased kinetics. In order to explore the stress generation mechanisms, the stress behaviors in the Sn films were observed under a variety of conditions. The results were able to be interpreted in terms of a simple model in which the stress is controlled primarily by the diffusion of atoms into and out of the grain boundary. Second, stress relaxation mechanisms were investigated during thermal cycles of electroplated Sn films. The observed stress relaxation behaviors were described well by a power-law creep mechanism. However, faster stress relaxation was observed in thicker films. It was also found through the surface etching experiment that the oxide layer plays an important role to prevent the stress relaxation. Third, a batch type method for the fabrication of free-standing large area Ni single crystal substrates was developed using epitaxial electrodeposition and selective etching processes. The substrates had no stress gradients along the thickness direction and very narrow distributions of crystallographic misorientation angles (~0.3ยบ). This fabrication method can be turned into a continuous process for long ribbons of single crystal substrates, which can be used for other applications.
epitaxial film growth
grain boundary
Thin films
Thesis (Ph.D.) -- Brown University (2009)
xix, 133 p.


Shin, Jae Wook, "Stress Generation and Relaxation in Thin Films: The Role of Kinetics and Grain Boundaries" (2008). Materials Science Engineering Theses and Dissertations, Engineering Theses and Dissertations. Brown Digital Repository. Brown University Library.