Ferroelectric capacitor with reduced imprint

Patent · Tue Dec 31 23:00:00 EST 1996

OSTI ID:871185

Warren, William L ^[1]; Tuttle, Bruce A ^[2]; Dimos, Duane B ^[3]; Pike, Gordon E ^[4]

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1. 7716 Wm. Moyers Ave., NE., Albuquerque, NM 87122
2. 12808 Lillian Pl., NE., Albuquerque, NM 87122
3. 6105 Innsbrook Ct., NE., Albuquerque, NM 87111
4. 1609 Cedar Ridge, NE., Albuquerque, NM 87112

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.

• Research Organization: Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA
• Assignee: Evans, Jr., Joseph T. (13609 Verbena Pl., NE., Albuquerque, NM 87112);Warren, William L. (7716 Wm. Moyers Ave., NE., Albuquerque, NM 87122);Tuttle, Bruce A. (12808 Lillian Pl., NE., Albuquerque, NM 87122);Dimos, Duane B. (6105 Innsbrook Ct., NE., Albuquerque, NM 87111);Pike, Gordon E. (1609 Cedar Ridge, NE., Albuquerque, NM 87112)
• Patent Number(s): US 5677825
• OSTI ID: 871185
• Country of Publication: United States
• Language: English

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