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Processing Effects for Integrated PZT: Residual Stress, Thickness, and Dielectric Properties
Author(s) -
Ong Ryan J.,
Payne David A.,
Sottos Nancy R.
Publication year - 2005
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/j.1551-2916.2005.00641.x
Subject(s) - materials science , dielectric , residual stress , composite material , wafer , ultimate tensile strength , stress (linguistics) , grain size , phase (matter) , optoelectronics , linguistics , philosophy , chemistry , organic chemistry
Processing effects on the dielectric properties of sol–gel‐derived PbZrO 3 –PbTiO 3 (PZT) films integrated onto Pt/Ti/SiO 2 //Si substrates are reported. Sol–gel synthesis and deposition conditions were designed to produce films of varying thickness (95–500 nm) with consistent chemical composition (Pb (Zr 0.53 Ti 0.47 )O 3 ), phase content (perovskite), grain size (∼110 nm), crystallographic orientation (nominally (111) fiber textured), and measured residual stress. The Stoney method, using laser reflectance to determine wafer curvature, derived biaxial tensile stress values of 150 and 180 MPa for PZT films after a baseline correction for electrode interactions during thermal processing was employed. The PZT films were of high dielectric quality, with low losses and negligible dispersion. Calculated values of dielectric constant ( K̄ ′) were found to decrease from 960 to 600 with decreasing film thickness. A series‐capacitor model successfully recovered a room‐temperature K 1 ′ for the PZT (1,170) in good agreement with bulk reports but was unable to reproduce the expected dielectric anomaly near 380°C. This discrepancy and the resulting diffuse phase transformation were attributed to the biaxial tensile stress present in the PZT films.