Effect of metallic oxides containing composite electrodes on crystallization and ferroelectric properties of Pb(Zr0.52,Ti0.48)O3 thin films deposited by the sol-gel method

In order to suppress polarization fatigue and decrease the leakage current of the PZT capacitor, composite electrodes consisting of MO2 (RuOx or IrOx) as an effective diffusion barrier and considerably large amounts of Pt were deposited by magnetron co-sputtering to yield heterostructured PZT capacitors, Pt/(Pt+MO2)//PZT(52/48)//(Pt+MO2)/(Pt+M)/M/Pt/Ti(Ta)/SiO2/Si(1 0 0), and the crystallinity and the orientation, the morphology of the surface and the cross section, and the composition depth profile of the PZT capacitor were examined by XRD analysis, SEM and AES, respectively, and the ferroelectric properties were measured. The results indicated that by adjusting the distribution and composition of the RuO2 phase, the polarization loss of the PZT capacitor can be suppressed to as small as 5% after polarization reversals of 10(9) while maintaining the effective polarization dP(r) = P-r* - P-r(boolean AND) at 15 mu C/cm(2). The suppression of the polarization fatigue was found more effective with (Pt+IrO2) electroding than (Pt+RuO2) electroding. The leakage current of the PZT capacitor electroded with (Pt+MO2) was a little larger than that of the PZT capacitor with Pt electrode. The possible reason was suggested.