Title:
Radiation-tolerant ferroelectric materials for multifunctional devices

dc.contributor.advisor Bassiri-Gharb, Nazanin
dc.contributor.author Chin, Evelyn
dc.contributor.committeeMember Vogel, Eric
dc.contributor.committeeMember Losego, Mark
dc.contributor.committeeMember Khan, Asif
dc.contributor.committeeMember Deo, Chaitanya
dc.contributor.department Materials Science and Engineering
dc.date.accessioned 2020-09-08T12:47:24Z
dc.date.available 2020-09-08T12:47:24Z
dc.date.created 2020-08
dc.date.issued 2020-07-14
dc.date.submitted August 2020
dc.date.updated 2020-09-08T12:47:24Z
dc.description.abstract Ferroelectric materials have switchable, spontaneous polarization in addition to strong dielectric, pyroelectric and piezoelectric response. In thin films form, these materials are leveraged for numerous microelectronic devices, including mechanical logic elements, optical sensors and transducers, precision positioners, energy harvesting units, nonvolatile memory storage, and microelectromechanical systems (MEMS) sensors and actuators. Ferroelectric materials have also become attractive for use in devices for radiation-hostile environments (e.g. aerospace, medical physics, x-ray/high energy source measurement tools, nuclear monitoring systems) due to their relatively high radiation tolerance. An increased understanding of material properties responsible for radiation tolerance will allow for development of materials for the next generation of radiation-tolerant, multifunctional devices. Lead zirconate titanate (PZT), one of the most commonly used ferroelectric materials for microscale applications, is widely known for its high polarization and piezoelectric response. However, increasing demand for smaller device footprint has pushed research efforts on PZT thin films towards their limitations, creating a need for new material systems to exceed the current standards. In this thesis, two material systems are explored as radiation tolerant ferroelectric alternatives to PZT: 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMN-PT) and Hf0.5Zr0.5O2 (HZO). PMN-PT films exhibit strong piezoelectric response, exceeding that of PZT, making them a strong candidate for next generation piezoelectric MEMS devices. Additionally, the large amount of chemical, polar, and structural heterogeneities in this material imply a large degree of entropy, which could result in accommodation of radiation-induced defects and enhanced radiation tolerance. HZO thin films exhibit strong polarization properties at only a few nanometers in thickness. Combined with its CMOS compatibility and the potential to fabricate complex 3D structures using atomic layer deposition, HZO has become an attractive material for (ferroelectric) non-volatile memory applications. Total ionization dose (TID) studies, using gamma-radiation doses up to 10 Mrad(Si), were performed to understand the radiation tolerance of PMN-PT and HZO thin films. Processing-structure-property relations were explored to identify the material characteristics responsible for both high functional response and high radiation tolerance. PMN-PT thin films were confirmed to exhibit equivalent or superior radiation tolerance in dielectric, polarization, and piezoelectric response than PZT thin films, largely unaffected by microstructural differences. Although the HZO thin films suffered significantly from aging, the films fabricated via plasma-enhanced atomic layer deposition exhibited superior radiation tolerance in polarization response than PZT thin films. The studies illustrate different pathways for concomitant enhanced functionality and higher radiation tolerance in ferroelectric thin films.
dc.description.degree Ph.D.
dc.format.mimetype application/pdf
dc.identifier.uri http://hdl.handle.net/1853/63647
dc.publisher Georgia Institute of Technology
dc.subject Ferroelectrics
dc.subject Thin films
dc.subject Relaxor-ferroelectrics
dc.subject Radiation exposure
dc.subject Total ionization dose
dc.title Radiation-tolerant ferroelectric materials for multifunctional devices
dc.type Text
dc.type.genre Dissertation
dspace.entity.type Publication
local.contributor.advisor Bassiri-Gharb, Nazanin
local.contributor.corporatename School of Materials Science and Engineering
local.contributor.corporatename College of Engineering
relation.isAdvisorOfPublication 4323cc13-897f-47cb-9043-03b0cdaa70ae
relation.isOrgUnitOfPublication 21b5a45b-0b8a-4b69-a36b-6556f8426a35
relation.isOrgUnitOfPublication 7c022d60-21d5-497c-b552-95e489a06569
thesis.degree.level Doctoral
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