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Title: Ferroelectric capacitor with reduced imprint

An improved ferroelectric capacitor exhibiting reduced imprint effects in comparison to prior art capacitors. A capacitor according to the present invention includes top and bottom electrodes and a ferroelectric layer sandwiched between the top and bottom electrodes, the ferroelectric layer comprising a perovskite structure of the chemical composition ABO.sub.3 wherein the B-site comprises first and second elements and a dopant element that has an oxidation state greater than +4. The concentration of the dopant is sufficient to reduce shifts in the coercive voltage of the capacitor with time. In the preferred embodiment of the present invention, the ferroelectric element comprises Pb in the A-site, and the first and second elements are Zr and Ti, respectively. The preferred dopant is chosen from the group consisting of Niobium, Tantalum, and Tungsten. In the preferred embodiment of the present invention, the dopant occupies between 1 and 8% of the B-sites.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5]
  1. (13609 Verbena Pl., NE., Albuquerque, NM 87112)
  2. (7716 Wm. Moyers Ave., NE., Albuquerque, NM 87122)
  3. (12808 Lillian Pl., NE., Albuquerque, NM 87122)
  4. (6105 Innsbrook Ct., NE., Albuquerque, NM 87111)
  5. (1609 Cedar Ridge, NE., Albuquerque, NM 87112)
Publication Date:
OSTI Identifier:
871185
Report Number(s):
US 5677825
Resource Type:
Patent
Research Org:
Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA
Country of Publication:
United States
Language:
English
Subject:
ferroelectric; capacitor; reduced; imprint; improved; ferroelectric; capacitor; exhibiting; reduced; imprint; effects; comparison; prior; capacitors; capacitor; according; top; bottom; electrodes; ferroelectric; layer; sandwiched; top; bottom; electrodes; ferroelectric; layer; comprising; perovskite; structure; chemical; composition; b-site; comprises; elements; dopant; element; oxidation; concentration; dopant; sufficient; reduce; shifts; coercive; voltage; capacitor; time; preferred; embodiment; ferroelectric; element; comprises; pb; a-site; elements; zr; respectively; preferred; dopant; chosen; consisting; niobium; tantalum; tungsten; preferred; embodiment; dopant; occupies; b-sites; perovskite structure; layer comprising; chemical composition; preferred embodiment; preferred embodiment; electric element; ferroelectric layer; ferroelectric layer; element comprises; bottom electrode; bottom electrode; reduced imprint; reduced imprint; dopant element; layer sandwiched; improved ferroelectric; exhibiting reduced; ferroelectric capacitor; ferroelectric capacitor; site comprises /361/