Thickness dependence of the time dependent dielectric breakdown characteristics of Pb(Zr, Ti)O-3 thin film capacitors for memory device applications

The time dependent dielectric breakdown characteristics of lead zirconate t itanate [Pb(Zr0.53Ti0.47)O-3] (PZT) thin thin capacitors are studied as a f unction of film thickness. The thickness of PZT films ranges from 70 nm to 470 nm, The variation of leakage current with electric field can be describ ed by a power law relationship. A power law can also describe the relation between the time to dielectric breakdown (t(BD)) and the electric field. Th e exponent of the first power law agrees very well with the second when the leakage current is measured using a short delay time of 0.1 s. An extrapol ation method was used to extract the tBD lifetime by correlating the t(BD) and the leakage current. The value of t(BD) lifetime increases from 10(4) s to 10(12) s as the film thickness is decreased from 470 nm to 70 nm. If th e leakage current is measured using a longer delay time (> 0.1 s), stress d egradation of the samples is observed.