Diffusion of oxygen tracer into deuterium-gas-baked IrO{sub x}/Pb(Zr,TiO{sub 3})Pt capacitors and Pb(Zr,Ti)O{sub 3}Pt films
- Fujitsu Limited and Fujitsu Laboratories Ltd., 10-1 Morinosato-Wakamiya, Atsugi 243-0197 (Japan)
Deuterium gas (D{sub 2}) ambient heat treatment of ferroelectric Pb(Zr,Ti)O{sub 3} (PZT) thin-film capacitors with a top electrode of iridium oxide and a bottom electrode of platinum showed significant polarization loss when baked at 200 deg. C at a pressure of 5 Torr. The D{sub 2} gas treatment of the capacitors partially reduced the iridium oxide (IrO{sub x}, where x is 1<x<2) film and increased surface roughness. In addition, a deuterium concentration [D] of 10{sup 20} at./cm{sup 3} in the degraded PZT was measured with secondary-ion mass spectroscopy (SIMS). Subsequently, the degraded films were annealed at 550 deg. C in oxygen ({sup 16}O{sub 2}) and oxygen tracer ({sup 18}O{sub 2}) gases which recovered the ferroelectric properties and the D concentration in the PZT decreased to the detection level of 10{sup 17} at./cm{sup 3}. The oxygen tracer concentration was highest in the IrO{sub x} film and much lower in the PZT. Comparison of the oxygen tracer SIMS profiles of the PZT annealed in tracer oxygen or preannealed in oxygen followed by oxygen tracer annealing showed little difference in the calculated PZT oxygen tracer diffusion coefficient of 5x10{sup -15} cm{sup 2}/s. If the PZT was reduced by the D{sub 2} gas, an increase in the oxygen diffusion coefficient would be expected as has been proposed in the literature, but this was not observed experimentally. These results indicate that the loss of polarization in the PZT capacitor is primarily due to the inhibition of ferroelectric domain switching by possible formation of [OD{sup -}].
- OSTI ID:
- 20719666
- Journal Information:
- Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 9 Vol. 98; ISSN JAPIAU; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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