Advances in Dielectric Materials and Electronic Devices: Dielectrics and Piezoelectrics: Session I Synthesis and Growth
Sponsored by: ACerS Electronics Division
Program Organizers: Amar Bhalla, University of Texas; Ruyan Guo, University of Texas at San Antonio; Rick Ubic, Boise State University; Danilo Suvorov, Jožef Stefan Institute
Tuesday 2:00 PM
November 3, 2020
Room: Virtual Meeting Room 9
Location: MS&T Virtual
Session Chair: Steven Tidrow, Alfred University; Vojislav Mitic, University Nis
2:00 PM Invited
Structural Peculiarities of Epitaxial PMN-PT Thin Films: Matjaž Spreitzer1; Urška Gabor1; Jamal Belhadi1; Nina Daneu1; Danilo Suvorov1; 1Jozef Stefan Institute
Pb(Mg1/3Nb2/3)O3–PbTiO3 is a relaxor ferroelectric material that exhibits interesting dielectric and piezoelectric properties. Specifically, complex domain architectures are formed in compositions around the morphotropic phase boundary. The polar structure of thin films is additionally affected by the epitaxial strain. In order to understand the structure of these films, multi-scale analysis is needed, considering the limitations of the individual analytical technique. Furthermore, it will be shown how macroscopic piezoelectric and dielectric measurements in different configurations can aid in understanding the film's structural characteristics. Growth-related aspects will also be discussed, with emphasis on the challenges and peculiarities occurring in the growth of films with volatile components. Routes for the preparation of single-phase films with near-nominal stoichiometry will be presented, along with the specific defects that appear with off-stoichiometry. It will be shown why in some cases a rough interface is preferred for phase purity and film quality.
2:40 PM
Novel Dielectrics, through [Ga, Ta] Dipolar-pair Substituted BaTiO3 Ceramics: Kaijie Ning1; Holly Shulman1; Steven Pilgrim1; Walter Schulze1; Steven Tidrow1; 1Alfred University
Ferroelectric- and relaxor-like properties in ceramics through dipole-pair substitutions offer a new route toward the future design of advanced electronic devices. [Ga, Ta] dipole-pair substituted BaTiO3 ceramics are fabricated and the respective microstructural, optical, electric and dielectric features are discussed. A fundamental understanding through new simple material model (NSMM) incorporating Clausius – Mossotti relation help explain the unusual dielectric behavior in these dipolar-pair substituted materials.
3:00 PM
Plasma-assisted Epitaxy and Piezoelectric Behavior of AlN Films on c-Sapphire: Morton Greenslit1; Robert Lad1; Mauricio Pereira da Cunha1; 1University of Maine
AlN films offer advantages compared to piezoelectric single crystal substrates for use in Surface Acoustic Wave (SAW) sensor devices, including flexible SAW device configurations, higher operating frequencies, and high temperature performance up to 800oC. In this work, a plasma-assisted epitaxy method is presented to achieve high quality AlN (0002) films on c-sapphire using e-beam evaporation of Al in an RF nitrogen plasma at a growth temperature of 930oC. A pre-nitridation treatment of sapphire was found to be beneficial in creating a seed layer for AlN epitaxy. RHEED analysis and XRD pole figures indicate that (0002) AlN grains also have in-plane registry with the sapphire substrate. SAW resonator devices operating near 450 MHz with different transducer and reflector configurations were patterned on the AlN/sapphire films. Admittance and impedance plots determined from S11 measurements indicate that defects and oxygen impurities in the AlN films strongly influence overall SAW resonator performance.
3:20 PM
Designing Electroceramics with Ferroelectric Grain Boundaries and Cold Sintering: Javier Mena-Garcia1; Clive Randall1; Sinan Dursun1; Kosuke Tsuji1; Sun Hwi Bang1; 1Pennsylvania State University
Using cold sintering, it has been able to demonstrate that novel phases, such as polymers, can be readily incorporated into the grain boundaries of a ceramic material. Typically, grain boundaries do not have ferroelectric activity; they are more likely to be inactive amorphous dielectric glass phases. Current research aims to consider dielectric oxide grains and a new type of ferroelectric intergranular phase based on organic/inorganic hybrid perovskite structures, and/or ionic ferroelectric polymers that are both ferroelectric active. By analyzing the microstructure of the ceramic-ferroelectric polymer composite, and characterizing its electrical and thermal properties, new families of ferroelectrics could be considered for new application opportunities in energy harvesting, capacitors, and actuators on flexible substrates. These materials and low temperature processes permit the possibility of hierarchical organic-inorganic functional composites ranging from the molecular level to the nanostructured phase distributions in the grain boundary phases.