• Title/Summary/Keyword: RuO$_2$

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The effects of PZT thin film capacitor with various bottom electrode (하부전극 변화에 따른 PZT 박막 특성에 관한 연구)

  • Park, Young;Chung, Kyu-Won;Yim, Seung-Hyuk;Song, Jun-Tae
    • Proceedings of the KIEE Conference
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    • pp.1986-1988
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    • 1999
  • Ferroelectric lead zirconate titanate(PZT) thin films were prepared on various bottom electrodes by rf magnetron sputtering methode. The structural phase and surface morphology of the PZT thin films were largely affected by the bottom electrodes. P-E curves of PZT thin films deposited on Pt. $RuO_2$ and Ru/$RuO_2$ bottom electrode showed typical P-E hysteresis loop. The measure values of $P_r,\;E_c$ of the Ru/PZT/Ru/$RuO_2$ capacitor were $16.9{\mu}C/Cm^2$, 140kV/ cm, respectively. The Ru/PZT/Ru/$RuO_2$ capacitors were fatigue free uP to nearly $10^9$ switching cycle but Pt/PZT/Pt capacitor showed 34% degradation uP to $10^9$ switching cycle.

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Electrical Characteristics of $(Ba,Sr)TiO_3/RuO_2$ Thin films

  • Park Chi-Sun
    • Journal of the Microelectronics and Packaging Society
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    • v.11 no.3
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    • pp.63-70
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    • 2004
  • The structural, electrical properties of $(Ba, Sr)TiO_3[BSTO]/RuO_2$ thin films were examined by the addition of amorphous BSTO layer between crystlline BSTO film and $RuO_2$ substrate. We prepared BSTO films with double-layered structure, that is, amorphous layers deposited at $60^{\circ}C$ and crystalline films. Crystalline films were prepared at 550 on amorphous BSTO layer. The thickness of the amorphous layers was varied from 0 to 170 nm. During the deposition of crystalline films, the crystallization of the amorphous layers occurred and the structure was changed to circular while crystalline BSTO films showed columnar structure. Due to insufficient annealing effect, amorphous BSTO phase was observed when the thickness of the amorphous layers exceeded 30 nm. Amorphous BSTO layer could also prevent the formation of oxygen deficient region in $RuO_2$ surface. Leakage current of total BSTO films decreased with increasing amorphous layer thickness due to structural modifications. Dielectric constant showed maxi-mum value of 343 when amorphous layer thickness was 30 nm at which the improvement by grain growth and the degradation by amorphous phase were balanced.

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Study on the Shift in the P-E Hysteresis Curve and the Fatigue Behavior of the PZT Capacitors Fabricated by Reactive Sputtering (반응성 스퍼터링법으로 형성시킨 PZT 커패시티의 P-E 이력곡선의 이동현상 및 피로 특성 연구)

  • Kim, Hyun-Ho;Lee, Won-Jong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.11
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    • pp.983-989
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    • 2005
  • [ $PZT(Pb(Zr,Ti)O_3)$ ] thin films were deposited by multi-target reactive sputtering method on $RuO_2$ substrates. Pure perovskite phase PZT films could be obtained by introducing Ti-oxide seed layer on the $RuO_2$ substrates prior to PZT film deposition. The PZT films deposited on the $RuO_2$ substrates showed highly voltage-shifted hysteresis loop compared with the films deposited on the Pt substrates. The surface of $RuO_2$ substrate was found to be reduced to metallic Ru in vacuum at elevated temperature, which caused the formation of oxygen vacancies at the initial stage of PZT film deposition and gave rise to the voltage shift in the P-E hysteresis loop of the PZT capacitor. The fatigue characteristics of the PZT capacitors under unipolar wane electric field were different from those under bipolar wane. The fatigue test under unipolar wane showed the increase of polarization. It was thought that the ferroelectric domains which had been pinned by charged defects such as oxygen vacancies and the charged defects were reduced in number by combining with the electrons injected from the electrode under unipolar wave, resulting in the relaxation of the ferroelectric domains and the increase of polarization.

Electrochemical Characteristics of Ruthenium Oxide Electrode-Organic Electrolyte System (유기전해액에서 루테늄산화물 전극의 전기화학적 특성)

  • Doh, Chil-Hoon;Choi, Sang-Jin;Moon, Seong-In;Yun, Mun-Soo;Yug, Gyeong-Chang;Kim, Sang-Gil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.1125-1128
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    • 2002
  • Electrochemical capacitor made with metal oxide electrode uses rapid and reversible protonation/deprotonation of metal oxide material under the aqueous acidic solution, generally. Electrochemical stability window of aqueous electrolyte-type capacitor is narrow compared to that of organic electrolyte-type capacitor. Electrochemical characteristics of electrochemical capacitor made with metal oxide electrode and lithium cation based organic electrolyte were evaluated. Electrochemical capacitor based on $RuO_2$ electrode material and 1M $LiPF_6$ in mixed solvents of EC, DEC, and EMC has anodic and cathodic specific capacitance of 145 and 142 F/g-$RuO_2{\cdot}nH_2O$, respectively, by using cyclic voltammetry with scan rate of 2 mV/sec g-$RuO_2$ in potential range of 2.0~4.2V(Li|$Li^+$).

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Structural Investigations of $RuO_2$ and Pt ad Films fir the Applications of memory Devices

  • S. M. Jung;Park, Y. S.;D. G. Lim;Park, Y.;J. Yi
    • Proceedings of the Korea Association of Crystal Growth Conference
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    • pp.57-60
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    • 1998
  • Lean zirconate titanate (PZT) is an attractive material for the memory device applications. We have investigated Pt and{{{{ { RuO}_{2 } }}}} as a botton electrode for a device application of PZT thin film. The bottom electrodes were prepared by using an RF magnetron sputtering method. The substrate temperature influenced the resistivity of Pt and {{{{ { RuO}_{2 } }}}} a s well as the film crystal structure. XRD examination shows that a preferred(111) orientations for the substrate temperature of 30$0^{\circ}C$. From the XRD and AFM results, we recommend the substrate temperature of 30$0^{\circ}C$ for the bottom electrode growth. We investigated and anneal temperature effect because Perovskite PZT structure is recommended for the memory device applications and the structural transformation is occurred only after and elevated heat treatment. As post anneal temperature was increased from RT to $700^{\circ}C$, the resistivity of Rt and {{{{ { RuO}_{2 } }}}} w as decreased. Surface morphology was observed by AFM as a function of post anneal temperature.

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RuO2-Doped TiO2 Nanotube Membranes Prepared via a Single-Step/Potential Shock Sequence

  • Yoo, Hyeonseok;Seong, Mijeong;Choi, Jinsub
    • Journal of Electrochemical Science and Technology
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    • v.10 no.3
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    • pp.271-275
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    • 2019
  • Anodic $TiO_2$ nanotubes were simultaneously grown and doped with $RuO_2$ by single-step anodization in a negatively-charged $RuO_4{^-}$ precursor. Subsequently, a high positive voltage was imposed on the nanotubes in an $F^-$-based electrolyte (a process referred to as potential shock), which led to the formation of a through-hole $RuO_2$-doped $TiO_2$ nanotube membrane without significant loss of the $RuO_2$ catalyst. XPS results confirmed that the doped Ru metal was converted into $RuO_2$ as the potential shock voltage increased. Further increases in the potential shock voltage led to the formation of $RuO_x/Ru$ in the $TiO_2$ nanotubes. All of our results clearly showed that a through-hole catalyst-doped $TiO_2$ nanotube membrane can be produced by a sequence consisting of single-step anodization and the potential shock process.