Thickness-dependent retention properties in polycrystalline Pb(Zr,Ti)O3 capacitors thinner than 100 nm

We studied the thickness-dependent retention properties in polycrystalline Ir/SrRuO3/Pb(Zr,Ti)O-3/Ir capacitors formed by metal-organic chemical vapor deposition, in which the Pb(Zr,Ti)O-3 layer thickness is 60 similar to 80 nm. Retention loss in Pb(Zr,Ti)O-3 capacitors is caused not by imprint (in long-time regime, > 1), but by polarization relaxation (in short-time regime, < 1). Such polarization relaxation becomes faster when film thickness decreases, which is a serious problem for high-density ferroelectric memories. Surface treatment can reduce retention loss (polarization relaxation) in short-time regime and leakage current. These improvements might originate from elimination of residue, such as PbO.