Effects of Ti/Ir top electrodes of PZT capacitors on the hydrogen related degradation |
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Authors: | Jiyoung Kim June-Mo Koo Tae Ho Kim Ilhwan Bang |
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Affiliation: | Department of Materials Engineering , Kookmin University , 861–1 JeongNeung-Dong, SungBuk-Gu, Seoul, 136-702, Korea |
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Abstract: | Abstract Hydrogen annealing damages on properties of PZT capacitors and a role of Ti/Ir hybrid structure top electrodes on capacitors are investigated in this study. It is demonstrated that the capacitors with Ti/Ir structure top electrodes improve a resistance against hydrogen related degradation. As the thickness ratio of Ti/Ir increases, the capacitors show enhanced endurance against hydrogen damages. Especially, PZT (350nm) capacitors with Ti(80nm)/Ir(20nm) hybrid top electrodes show only 26% decrease in nonvolatile polarizations (P?r) under ± 7V, while 67% of P?r of ferroelectric capacitors with Ir top electrodes is reduced after forming gas annealing at 250°C for 10min. Based on the XPS analysis, ferroelectric characteristics of PZT thin film capacitors are degraded by destruction of Pb-O bond into metallic Pb due to hydrogen anneal on the catalytic top electrodes (Ir, Pt). |
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Keywords: | PZT ferroelectric FeRAM hydrogen forming gas hybrid electrode |
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