Thickness Dependence of the Time Dependent Dielectric Breakdown Characteristics of Pb(Zr, Ti)O_3 Thin Film Capacitors for Memory Device Applications

概要

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The time dependent dielectric breakdown characteristics of lead zirconate titanate [Pb(Zr_<0.53>Ti_<0.47>)O_3] (PZT) thin film capacitors are studied as a function 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 described 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. The 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 extrapolation method was used to extract the t_<BD> lifetime by correlating the t_<BD> and the leakage current. The value of t_<BD> lifetime increases from 10^4s to 10^<12>s as the film thickness is decreased from 470 nm to 70 nm. If the leakage current is measured using a longer delay time (> 0.1s), stress degradation of the samples is observed.
社団法人応用物理学会の論文
2000-06-15