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Additively patterned ferroelectric thin films with vertical sidewalls
Author(s) -
Welsh Aaron J.,
Dezest Denis,
Nicu Liviu,
TrolierMcKinstry Susan
Publication year - 2017
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.14566
Subject(s) - materials science , lead zirconate titanate , wafer , microelectromechanical systems , ferroelectricity , optoelectronics , thin film , silicon , piezoelectricity , micrometer , composite material , dielectric , nanotechnology , optics , physics
The functional properties of electroceramic thin films can be degraded by subtractive patterning techniques used for microelectromechanical ( MEMS ) applications. This work explores an alternative deposition technique, where lead zirconate titanate ( PZT ) liquid precursors are printed onto substrates in a desired geometry from stamp wells (rather than stamp protrusions). Printing from wells significantly increased sidewall angles (from ~1 to >35 degrees) relative to printing solutions from stamp protrusions. Arrays of PZT features were printed, characterized, and compared to continuous PZT thin films of similar thickness. Three‐hundred‐nanometer‐thick printed PZT features exhibit a permittivity of 730 and a loss tangent of 0.022. The features showed remanent polarizations of 26 μC/cm 2 , and coercive fields of 95 kV /cm. The piezoelectric response of the features produced an e 31,f of −5.2 C/m 2 . This technique was also used to print directly atop prepatterned substrates. Optimization of printing parameters yielded patterned films with 90° sidewalls. Lateral feature sizes ranged from hundreds of micrometers down to one micrometer. In addition, several device designs were prepatterned onto silicon on insulator ( SOI ) wafers (Si/SiO 2 /Si with thicknesses of 0.35/1/500 μm). The top patterned silicon was released from the underlying material, and PZT was directly printed and crystallized on the free‐standing structures.