The effects of La and Nb modification on fatigue and retention properties of Pb(Ti, Zr)O-3 thin-film capacitors

The effects of La and Nb modification on fatigue and retention properties of Pb(Ti, Zr)O-3 thin-film capacitors with Ir electrodes formed by sol-gel deposition were evaluated. The concentrations of La and Nb are 1 atm%. The columnar-grain-structured Pb(Ti, Zr)O-3 was unchanged by La- and Nb-modification on Ir substrates. They showed good fatigue resistance properties. However, marked degradation of polarization density and retention property was observed clearly. Remanent polarization density was decreased markedly by La modification. La and Nb modified Pb(Ti, Zr)O-3 thin-film capacitors showed large losses of 39.0% and 37.5% in remanent polarization density in the first second as compared to the loss of 11.4% for a nonmodified one, Furthermore, the secondary loss is increased significantly by Nb modification. Thus, a nonmodified Pb(Ti, Zr)Oa thin-film capacitor with Ir electrodes shows better fatigue and retention properties than La and Nb modified capacitors.