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Rafael Reif. Hsieh, Peter Y. (Peter Yaw-ming), 1975- Massachusetts Institute of Technology. Department of Materials Science and Engineering 2005-08-19T19:49:13Z 2005-08-19T19:49:13Z 1999 1999 http://hdl.handle.net/1721.1/9736 42720677 Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1999. Includes bibliographical references (p. 59-60). Microelectromechanical systems (MEMS) often incorporate piezoelectric thin films to actuate and detect motion of mechanical structures. Aluminum nitride is advantageous for MEMS use because it can be deposited at low temperatures, is easily patterned using conventional photolithographic techniques, and is compatible with CMOS contaminant requirements for silicon IC foundries. In this work, AIN thin films were deposited on silicon for use in a MEMS ultrasonic resonator. The resonator is configured as a gravimetric chemical sensor. A rotatable central composite designed experiment was performed to optimize film properties affecting device performance: film crystallinity, stress, and uniformity. Film property response characterization was conducted with x-ray diffractometry, spectroscopic ellipsometry, and surface profilometry. Optimization of film deposition parameters improved AIN film properties in the MEMS sensors. Film property characterization using response surface methodology indicated microstructural changes due to sputtered particle bombardment of the growing film surface. Surface morphology of the sputtered AIN films was assessed using tapping mode atomic force microscopy and scanning electron microscopy. Energetic particle bombardment of the growing film surface helped to yield dense crystalline films with zone T microstructure. Thermalization of the impinging particle flux resulted in voided films with zone 1 microstructure with inferior film properties. Correlation between film crystallinity and oxygen content was explored with x-ray photoelectron spectrometry. Changes in film microstructure and composition are correlated with variations in deposition parameters. Adatom mobility during film growth appears to play an important role in determining final film properties. by Peter Y. Hsieh. S.M. 60 p. 5264955 bytes 5264715 bytes application/pdf application/pdf eng Massachusetts Institute of Technology M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 Materials Science and Engineering DC magnetron reactive sputtering of low stress AlN piezoelectric thin films for MEMS application Direct current magnetron reactive sputtering of low stress aluminum nitride piezoelectric thin films for microelectromechanical systems application Thesis application/pdf false Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="82e0fb67-5b5b-4336-81a7-e88cd6173d58"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>DC magnetron reactive sputtering of low stress AlN piezoelectric thin films for MEMS application</Title> <Subtitle>Direct current magnetron reactive sputtering of low stress aluminum nitride piezoelectric thin films for microelectromechanical systems application</Subtitle> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>1999</PublicationDate> <Authors> <Author> <DisplayName>Hsieh, Peter Y. (Peter Yaw-ming), 1975-</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Materials Science and Engineering</Keyword> <Abstract>Microelectromechanical systems (MEMS) often incorporate piezoelectric thin films to actuate and detect motion of mechanical structures. Aluminum nitride is advantageous for MEMS use because it can be deposited at low temperatures, is easily patterned using conventional photolithographic techniques, and is compatible with CMOS contaminant requirements for silicon IC foundries. In this work, AIN thin films were deposited on silicon for use in a MEMS ultrasonic resonator. The resonator is configured as a gravimetric chemical sensor. A rotatable central composite designed experiment was performed to optimize film properties affecting device performance: film crystallinity, stress, and uniformity. Film property response characterization was conducted with x-ray diffractometry, spectroscopic ellipsometry, and surface profilometry. Optimization of film deposition parameters improved AIN film properties in the MEMS sensors. Film property characterization using response surface methodology indicated microstructural changes due to sputtered particle bombardment of the growing film surface. Surface morphology of the sputtered AIN films was assessed using tapping mode atomic force microscopy and scanning electron microscopy. Energetic particle bombardment of the growing film surface helped to yield dense crystalline films with zone T microstructure. Thermalization of the impinging particle flux resulted in voided films with zone 1 microstructure with inferior film properties. Correlation between film crystallinity and oxygen content was explored with x-ray photoelectron spectrometry. Changes in film microstructure and composition are correlated with variations in deposition parameters. Adatom mobility during film growth appears to play an important role in determining final film properties.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>