Characterization of lead zirconate titanate (PZT) thin films for ferroelectric memory applications.

Persistent Link:
http://hdl.handle.net/10150/186318
Title:
Characterization of lead zirconate titanate (PZT) thin films for ferroelectric memory applications.
Author:
Lee, Sungchul.
Issue Date:
1993
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Recently, significant progress has been made in integrating ferroelectric materials and semiconductor technology to achieve high density, semiconductor memories. The hysteresis behavior of the polarization versus the electric field and high dielectric constant of ferroelectric materials are useful for non-volatile and dynamic random access memories (DRAMs), respectively. Lead Zirconate-Titanate (Pb(Zr,Ti)O₃), commonly called PZT, is considered to be potentially important in memory applications. PZT is the ferroelectric material studied here. In this dissertation, the measurement methods for polarization and current-voltage characteristics of ferroelectric thin films are investigated. A new method for measuring current-voltage characteristics of ferroelectric materials is developed to distinguish the leakage current from the switching current. Further, the reliability concerns for ferroelectric memories, such as fatigue, retention, and temperature effect, are discussed based on the polarization and leakage-current characteristics of sol-gel derived PZT thin films. In addition to the studies on the charge storage capability, a model of the ferroelectric thin films is presented. Considering the spontaneous polarization of the ferroelectric film, a back-to-back Schottky barrier system having asymmetric barriers is proposed as a model for the platinum-PZT-platinum capacitor. The potential and electric field distributions in PZT thin films are calculated by solving Poisson's equation numerically for different doping concentrations. In this analysis, the permittivity variation with respect to the electric field is considered. Based on these numerical results, capacitance-voltage characteristics of the PZT thin film capacitor are predicted. For a doping concentration of 1 x 10¹⁸ cm⁻³ and the maximum relative permittivity of ∼8000, the calculated C-V curve fits well with the experimental result.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Dissertations, Academic.; Electrical engineering.; Materials science.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Electrical and Computer Engineering; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Schrimpf, Ronald D.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleCharacterization of lead zirconate titanate (PZT) thin films for ferroelectric memory applications.en_US
dc.creatorLee, Sungchul.en_US
dc.contributor.authorLee, Sungchul.en_US
dc.date.issued1993en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractRecently, significant progress has been made in integrating ferroelectric materials and semiconductor technology to achieve high density, semiconductor memories. The hysteresis behavior of the polarization versus the electric field and high dielectric constant of ferroelectric materials are useful for non-volatile and dynamic random access memories (DRAMs), respectively. Lead Zirconate-Titanate (Pb(Zr,Ti)O₃), commonly called PZT, is considered to be potentially important in memory applications. PZT is the ferroelectric material studied here. In this dissertation, the measurement methods for polarization and current-voltage characteristics of ferroelectric thin films are investigated. A new method for measuring current-voltage characteristics of ferroelectric materials is developed to distinguish the leakage current from the switching current. Further, the reliability concerns for ferroelectric memories, such as fatigue, retention, and temperature effect, are discussed based on the polarization and leakage-current characteristics of sol-gel derived PZT thin films. In addition to the studies on the charge storage capability, a model of the ferroelectric thin films is presented. Considering the spontaneous polarization of the ferroelectric film, a back-to-back Schottky barrier system having asymmetric barriers is proposed as a model for the platinum-PZT-platinum capacitor. The potential and electric field distributions in PZT thin films are calculated by solving Poisson's equation numerically for different doping concentrations. In this analysis, the permittivity variation with respect to the electric field is considered. Based on these numerical results, capacitance-voltage characteristics of the PZT thin film capacitor are predicted. For a doping concentration of 1 x 10¹⁸ cm⁻³ and the maximum relative permittivity of ∼8000, the calculated C-V curve fits well with the experimental result.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectDissertations, Academic.en_US
dc.subjectElectrical engineering.en_US
dc.subjectMaterials science.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineElectrical and Computer Engineeringen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.chairSchrimpf, Ronald D.en_US
dc.contributor.committeememberGalloway, Kenneth F.en_US
dc.contributor.committeememberBrews, John R.en_US
dc.contributor.committeememberMazumdar, Sumitendraen_US
dc.identifier.proquest9333323en_US
dc.identifier.oclc720028460en_US
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