PZT thin films for ferroelectric capacitor and method for preparing the same
US5625529A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 28, 1995 |
| Grant date | Apr 29, 1997 |
| Priority date | — |
| Expiry date | Mar 28, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/435
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
PZT ferroelectric thin films for capacitors comprise a combination of a donor dopant and an acceptor dopant in a total amount of about 0.1 to 8 mole percent of PZT, or Sc alone in an amount of about 0.1 to 5 mole percent. Nb or Ta is employed as a donor dopant, while Sc, Mg or Zn can be used as an acceptor dopant. The presence of a single Sc acceptor dopant, or both an acceptor dopant and a donor dopant, results in increased endurance. Fatigue cycles are increased on the order of about 10.sup.5 relative to dopant-free films. Doping with a single Sc acceptor dopant, or both an acceptor dopant and a donor dopant, reduces coercive field, allowing PZT films to switch at relatively low voltages. PZT thin films of a pure perovskite phase are obtained in which a pyrochlore phase is completely excluded. Pt may be used as an electrode material. The leakage current of PZT films doped with both the acceptor and donor elements are similar to the leakage current level of pure PZT thin films.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.