Processing Optimization of Lead Magnesium Niobate‐Lead Titanate 
Thin Films for Piezoelectric MEMS Application

Abstract

We report processing conditions and electromechanical properties of highly textured, 0.7Pb(Mg 1/3 Nb 2/3 )O 3 -0.3PbTiO 3 (PMN-PT) films, processed via chemical solution deposition on platinized silicon substrates. Textured perovskite seed layers, optimization of heat treatment conditions and Pb content control were studied to obtain pure perovskite PMN-PT films with dense, columnar grains. Highly (100)-and (111)-oriented films, with Lotgering factors between 91% and 97%, and average grain size up to~430 nm were synthesized on thin PbTiO 3 and Pb(Zr,Ti)O 3 seed layers. Overall, (100)-textured films showed higher dielectric permittivity and saturated d 33,f piezoelectric coefficients. Dense, submicron-thick, (100)-oriented films showed low-field, relative dielectric permittivity of up tõ 2850 (tan d = 0.02) at 1 kHz, and remnant polarization values up to 17.5 lC/cm 2 . The films showed saturated d 33,f piezoelectric coefficients as high as 210 pm/V. D. Viehland-contributing editor Manuscript No. 30202.

Thickness‐dependent domain wall reorientation in 70/30 lead magnesium niobate‐ lead titanate thin films

“…Such rotation has been observed as a function of PZT film thickness, and is attributed to residual stress levels or strain gradients through the thickness of the films . Epitaxial films, on the other hand, are more square in shape and exhibit no significant trend in P r or P max , but do show increased E C upon thickness reduction, as is commonly reported in the literature . The increase in coercive field with decreasing film thickness has previously been attributed to a higher density of strong domain pinning sites at the film‐electrode interfaces .…”

“…61,62 Epitaxial films, on the other hand, are more square in shape and exhibit no significant trend in P r or P max , but do show increased E C upon thickness reduction, as is commonly reported in the literature. 28,51,63,64 The increase in coercive field with decreasing film thickness has previously been attributed to a higher density of strong domain pinning sites at the film-electrode interfaces. 28,51 The loop width in polycrystalline films slightly decreases with film thickness, however.…”

“…As discussed above, numerous factors contribute to the size effects of ferroelectric films. To support the integration of high strain relaxor‐ferroelectrics in the aforementioned devices, this work aims to identify the dominant mechanisms of thickness dependence in 70PMN‐30PT, especially at thicknesses below 600 nm where PMN‐PT can be grown crack‐free on Si . The 70PMN‐30PT films were grown by chemical solution deposition (CSD) in a thickness series from 100 to 350 nm on two different substrates.…”

“…To support the integration of high strain relaxor-ferroelectrics in the aforementioned devices, this work aims to identify the dominant mechanisms of thickness dependence in 70PMN-30PT, especially at thicknesses below 600 nm where PMN-PT can be grown crack-free on Si. [48][49][50][51] The 70PMN-30PT films were grown by chemical solution deposition (CSD) in a thickness series from 100 to 350 nm on two different substrates. Strongly {001} oriented polycrystalline films were grown on platinized Si substrates, while SrTiO 3 single crystals with SrRuO 3 bottom electrodes were employed for growth of epitaxial {001} PMN-PT.…”

Improvement of reliability and dielectric breakdown strength of Nb‐doped lead zirconate titanate films via microstructure control of seed

“…This dependency is attributed to Pb loss through the bottom Pt electrode and PbO vaporization during processing . As the Pb deficiency increases, the pyrochlore phase is favored (Pb‐rich films favor the perovskite phase) . Figure B‐E shows microstructures of MPB PNZT seed layers with increasing amounts of Pb excess in the solution.…”