Phase-Change Materials in Optically Triggered Microactuators

• Published in: Journal of microelectromechanical systems Vol. 17; no. 5; pp. 1094 - 1103
• Main Authors: Kalb, J.A., Qiang Guo, Xiaoqiang Zhang, Yi Li, Chornghaur Sow, Thompson, C.V.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-10-2008; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Actuators; Applied sciences; CD recording; Deflection; Density; Devices; Digital video disks; Electronics; Exact sciences and technology; Flash memory; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; laser annealing; Laser modes; Magnetic and optical mass memories; Materials selection; Mathematical models; Mechanical instruments, equipment and techniques; Microactuators; Micromechanical devices and systems; Optical films; Optical materials; Phase change materials; Phase change random access memory; Phase transformations; Physics; Sputtering; Storage and reproduction of information; stress measurement; tellurium alloys; Thin film devices; Actuators; stress measurement; tellurium alloys; laser annealing; Annealing; Heat treatment; Probabilistic approach; Compact disk; Optical memory; Microactuators; Modeling; Optimization; Cantilever beam; Thin film; Phase transformation; DVD; Flash memory; Non volatile memory; PCM material; Microelectromechanical device; Actuator
• ISSN: 1057-7157; 1941-0158
• DOI: 10.1109/JMEMS.2008.928708

Phase-change materials have been extensively used for optical data storage in commercial rewritable compact disks and digital video disks. These materials are also widely considered for next-generation phase-change random access memories to replace current Flash memories. We suggest a different application of phase-change materials in optically triggered microactuators. The suggested device consists of a thin film of a phase-change material deposited on a microfabricated cantilever. A laser-induced phase transformation in the film initiates a cantilever deflection since the transformation is accompanied by a large density change. We analyze quantitative criteria for material selection and optimization of device dimensions for the largest possible actuation angles and deflections. The resulting analytical model is both verified numerically and applied experimentally. Furthermore, we show that these cantilevers offer a convenient way to measure film stresses and film strains associated with laser-induced phase transformations.