THERMALLY STIMULATED CURRENT AND POLARIZATION FATIGUE IN PB(ZR,TI)O-3THIN-FILMS

In order to clarify the origin of the polarization fatigue phenomena, charge traps in ferroelectric Pb(Zr,Ti)O-3 (PZT) thin films were measu red using the thermally stimulated current (TSC) technique. For polari zation fatigued Pt/PZT/Pr/SiO2/Si(100) capacitors, a peak of TSC was o bserved, and the trap density estimated from the TSC data increased as switching cycles increased. Activation energy and density of the char ge traps were estimated to be 0.7-0.8 eV and on the order of 10(18) cm (-3), respectively. It was also observed that degradation of remanent polarization of PZT was improved by the TSC measurement process. On th e other hand, no TSC peak was observed for fatigue free Ir/PZT/Ir/IrO2 /SiO2/Si(100) capacitors. From these results, it was suggested that th e main origin of the polarization fatigue phenomena was the domain pin ning caused by trapped charge carriers injected by polarization revers al.