Microstructure, residual stress, and mechanical properties of thin film materials for a microfabricated solid oxide fuel cell

The microstructure and residual stress of sputter-deposited films for use in microfabricated solid oxide fuel cells are presented. Much of the work focuses on the characterization of a candidate solid electrolyte: Yttria Stabilized Zirconia (YSZ). Stress and structure of reactive RF sputtered YSZ films are explored as a function of thickness (5nm - 1000nm), deposition pressure (5mtorr - 1OOmtorr), and substrate temperature (room temperature, 3000C and 6000C). Microstructure is characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Film composition, specifically impurity content, is investigated with secondary ion mass spectroscopy (SIMS). Results indicate that YSZ films likely have a columnar structure with fully cubic crystalline phases of (100) texture with mixed amorphous/crystalline phases. Residual stress is measured via substrate curvature techniques. Results indicate that the as-deposited residual stress of YSZ ranges from -1.4 GPa to 400MPa with variations in sputtering conditions. Transitions from compressive to tensile stress are identified with variations in working pressure and film thickness.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2006

Author dc:creator

• Quinn, David John, Sc. D. Massachusetts Institute of Technology

Advisor dc:contributor.advisor

• Brian L. Wardle.

• Mechanical Engineering.

Statement dc:rights

• 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.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/36244

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/36244