30 August 1999 Ion beam sputter deposition of TiNi shape memory alloy thin films
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Proceedings Volume 3874, Micromachining and Microfabrication Process Technology V; (1999) https://doi.org/10.1117/12.361219
Event: Symposium on Micromachining and Microfabrication, 1999, Santa Clara, CA, United States
The development of functional or smart materials for integration into microsystem is of increasing interest. An example is the shape memory effect exhibited by certain metal alloys which, in principle, can be exploited in the fabrication of micro-scale manipulators or actuators, thereby providing on-chip micromechanical functionality. We have investigated an ion beam sputter deposition process for the growth of TiNi shape memory alloy thin films and demonstrated the required control to produce equiatomic composition, uniform coverage and atomic layer-by-layer growth rates on engineering surfaces. The process uses argon ions at intermediate energy produced by a Kaufman-type ion source to sputter non-alloyed targets of high purity titanium and nickel. Precise measurements of deposition rates allows compositional control during thin film growth. As the sputtering targets and substrates are remote from the discharge plasma, deposition occurs under good vacuum of approximately 10-6 mtorr thus promoting high quality films. Furthermore, the ion beam energetics allow deposition at relatively low substrate temperatures of < 150 degrees C with as-deposited films exhibiting shape memory properties without post-process high temperature annealing. Thermal imagin is used to monitor changes which are characteristic of the shape memory effect and is indicative of changes in specific heat capacity and thermal conductivity as the TiNi shape memory alloy undergoes martensitic to austenitic phase transformations.
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Sam T. Davies and Kazuyoshi Tsuchiya "Ion beam sputter deposition of TiNi shape memory alloy thin films", Proc. SPIE 3874, Micromachining and Microfabrication Process Technology V, (30 August 1999); doi: 10.1117/12.361219; https://doi.org/10.1117/12.361219

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