Quantitative piezoelectric measurements of partially released Pb(Zr, Ti)O3 structures
Year: 2024
Type: article
Abstract: The effective large signal longitudinal piezoelectric coefficient (d33,f∗) of piezoelectric thin films on rigid substrates has been widely investigated. Unclamped piezoelectric thin films are predicted to have a higher d33,f∗ coefficient due to reduced constraints on piezoelectric strain, domain reorientation, and domain wall motion, but quantitative measurements of this coefficient have been limited. This study uses microfabrication techniques along with double-beam laser interferometry (DBLI) to accurately determine the longitudinal piezoelectric coefficient of Pb(Zr,Ti)O3 thin films in partially released piezomicroelectromechanical structures. A two-step backside release process was used: first, deep reactive ion etching to create backside vias and second, wet etching of the ZnO sacrificial layer to release the area beneath the Pb(Zr,Ti)O3 thin films. Post wet etching, optical profilometry showed concavely deformed diaphragms resulting from asymmetrical stress profiles through the diaphragm thickness. DBLI was then used to examine diaphragm deflection under an applied unipolar voltage ranging from 0 to 10 V. Devices with 50% and 75% of the area beneath the top electrode released exhibited large signal d33,f∗ values of 410 ± 6 and 420 ± 8 pm/V, respectively, more than three times higher than the d33,f∗ value of the clamped samples: 126 ± 13 pm/V. The reasons contributing to the large d33,f∗ include (i) the change in stress levels due to the release process, (ii) the elimination of mechanical constraints from substrate clamping, and (iii) enhanced domain reorientation. These findings confirm that substrate declamping significantly boosts the piezoelectric coefficient, bringing d33,f∗ closer to the bulk longitudinal piezoelectric coefficient (d33).
Source: Journal of Applied Physics
DOI: 10.1063/5.0215677
Institution: Pennsylvania State University
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,500
Awards: G2862132367, G4277278267, WE PROPOSE TO BUILD AND TEST THIN FILM TRANSISTOR CONTROL CIRCUITRY FOR A NEW HIGH RESOLUTION ADJUSTABLE X RAY MIRROR TECHNOLOGY. THIS CONTROL CIRCUITRY WILL GREATLY SIMPLIFY THE WIRING SCHEME TO ADDRESS INDIVIDUAL ACTUATOR CELLS. THE RESULT WILL BE A TRANSFORMATIVE IMPROVEMENT FOR THE X RAY SURVEYOR MISSION CONCEPT MATHEMATICAL MODELS WHICH FIT THE EXPERIMENTAL DATA QUITE WELL INDICATE THAT0.5 ARCSECOND IMAGING IS FEASIBLE THROUGH THIS TECHNIQUE UTILIZING THIN SLUMPED GLASS SUBSTRATES WITH UNCORRECTED ANGULAR RESOLUTION OF ORDER 5 10 ARCSECONDS.IN ORDER TO CORRECT FOR FIGURES ERRORS IN A TELESCOPE WITH SEVERAL SQUARE METERS OF COLLECTING AREA MILLIONS OF ACTUATOR CELLS MUST BE SET AND HELD AT SPECIFIC VOLTAGES. IT IS CLEARLY NOT FEASIBLE TO DO THIS VIA MILLIONS OF WIRES EACH ONE CONNECTED TO AN ACTUATOR. INSTEAD WE PROPOSE TO DEVELOP AND TEST THIN FILM TECHNOLOGY THAT OPERATES ON THE SAME PRINCIPLE AS MEGAPIXEL COMPUTER SCREENS. WE WILL DEVELOP THE TECHNOLOGIES NEEDED TO BUILD THIN FILM PIEZOELECTRIC ACTUATORS CONTROLLED BY THIN FILM ZNO TRANSISTORS ON FLEXIBLE POLYIMIDE FILMS AND TO CONNECT THOSE FILMS TO THE BACK SURFACES OF X RAY MIRRORS ON THIN GLASS SUBSTRATES WITHOUT DEFORMING THE SURFACE. THESE TECHNOLOGIES REPRESENT A PROMISING AVENUE OF THE DEVELOPMENT OF MIRRORS FOR THE X RAY SURVEYOR MISSION CONCEPT.SUCH A TELESCOPE WILL MAKE POSSIBLE DETAILED STUDIES OF A WIDE VARIETY OF ASTROPHYSICAL SOURCES. ONE EXAMPLE IS THE WARM HOT INTERGALACTIC MEDIUM WHIM WHICH IS THOUGHT TO ACCOUNT FOR A LARGE FRACTION OF THE NORMAL MATTER IN THE UNIVERSE BUT WHICH HAS NOT BEEN DETECTED UNAMBIGUOUSLY TO DATE. ANOTHER IS THE GROWTH OF SUPERMASSIVE BLACK HOLES IN THE EARLY UNIVERSE.THIS PROPOSAL SUPPORTS NASAS GOALS OF TECHNICAL ADVANCEMENT OF TECHNOLOGIES SUITABLE FOR FUTURE MISSIONS AND TRAINING OF GRADUATE STUDENTS., G897291506
OpenAlex ID: W4402172260