• Title/Summary/Keyword: c-axis preferred orientation

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Effects of Thermal Heat Treatment Process on the Ferroelectric Properties of ReMnO3 (Re:Ho, Er) Thin Films (ReMnO3(Re:Ho, Er) 박막의 강유전성에 미치는 열처리 공정의 영향)

  • Kim, Eung-Soo;Chae, Jung-Hoon
    • Journal of the Korean Ceramic Society
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    • v.42 no.11
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    • pp.763-769
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    • 2005
  • Ferroelectric $ReMnO_3$(Re:Ho, Er) thin films were deposited on Si(100) substrate by Metal-Organic Chemical Vapor Deposition (MOCVD). Crystallinity and electric properties of $ReMnO_3$(Re:Ho, Er) thin films were investigated as a function of thermal heat treatment process, CHP (Conventional Heat-treatment Process) and RTP (Rapid Thermal Process). $ReMnO_3$(Re:Ho, Er) thin films prepared by RTP showed higher c-axis preferred orientation and homogeneous surface roughness than those prepared by CHP. The remnant polarization of ferroelectric hysteresis loop of $ReMnO_3$(Re:Ho, Er) thin films was strongly dependent on the c­axis preferred orientation of hexagonal single phase, and the leakage current characteristics of thin films were dependent on the homogeneity of grain size as well as surface roughness of thin films.

A Study on the Deposition Characteristics of ZnO Piezoelectric Thin film Bulk Acoustic Resonator (FBAR 응용을 위한 ZnO 압전 박막의 증착 특성에 관한 연구)

  • 최승혁;김종성
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.16 no.8
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    • pp.716-722
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    • 2003
  • ZnO thin films were deposited on Al and Pt electrodes by an RF reactive sputtering system for the fabrication of FBAR (film bulk acoustic wave resonator), and the effect of thermal treatment temperature on their c-axis preferred orientation was investigated. SEM experiments show that columnar structure of ZnO thin films were grown with c-axis normal to electrode material, and XRD experiments show that both ZnO films were grown with (002) plane preferred orientation, but larger diffraction peak was observed with Pt electrode. The peak intensity increased with higher thermal treatment temperature, but c-axis preferred orientation was diminished. The surface roughness of Al thin film was higher than that of Pt, and these affect the surface roughness of ZnO film deposited on the electrode. Though the preferred orientation with respect to Pt(111) plane was improved with higher thermal treatment temperature, this could not improve the c-axis orientation of ZnO film.

Preparation AZO(ZnO:Al) thin film for FBAR by FTS method (대향타겟스퍼터링법에 의한 FBAR용 AZO(ZnO:Al) 전극의 제작)

  • Keum, M.J.;Shin, S.K.;Ga, C.H.;Chu, S.N.;Kim, K.H.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.172-175
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    • 2003
  • ZnO:Al thin film for application to FBAR's bottom electrode using ZnO piezoelectric thin film were prepared by FTS, in order to improve the crystallographic properties of ZnO thin films because the ZnO:Al thin film and ZnO thin films structure is equal each other. So we prepared the ZnO:Al thin film with oxygen gas flow rate. Thickness and c-axis preferred orientation and electric properties of ZnO:Al bottom electrode were evaluated by $\alpha$-step, XRD and 4-point probe..

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Effects of Oxygen Pressure on the Crystallization Behavior and Electrical Properties of YMnO3 Thin Films

  • Cheon, Chae-Il;Yun, Kwi-Young;Kim, Jeong-Seog;Kim, Jin-Hyeok
    • Journal of the Korean Ceramic Society
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    • v.40 no.4
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    • pp.398-400
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    • 2003
  • The YMnO$_3$ thin films were prepared on platinized-silicon substrates by chemical solution deposition and annealed at 750 to 85$0^{\circ}C$ for 1 h under various oxygen pressures, from 2 mTorr to 760 Torr. Effects of annealing oxygen pressures on the crystallization behavior and electrical properties of YMnO$_3$ thin films were investigated. Crystallinity and c-axis preferred orientation of YMnO$_3$ thin film were improved by decreasing the oxygen pressure but were deteriorated at extremely low oxygen pressure, 2 mTorr. Leakage current density of the YMn03 thin film decreased as the oxygen pressure decreased. The film annealed at 80$0^{\circ}C$ under 2 Torr, which had the best crystallinity and the highest c-axis preferred orientation. showed the best-developed ferroelectric C-V hysteresis.

Dependence of Ferroelectric Properties on the Crystalline Phases of HoMnO3 Thin Film (HoMnO3 박막의 강유전 특성의 결정상 의존성)

  • Kim, Eung-Soo;Kang, Dong-Ho
    • Korean Journal of Materials Research
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    • v.16 no.6
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    • pp.394-399
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    • 2006
  • Ferroelectric $HoMnO_3$ thin films were deposited on the Si(100) substrate at $700^{\circ}C$ for 2 hrs by metalorganic chemical vapor deposition (MOCVD) and post-annealed at 850oC by rapid thermal process (RTP). Electrical properties and crystalline phases of $HoMnO_3$ thin films were investigated as a function of postannealing time. Single phase of hexagonal symmetry with c-axis preferred orientation was obtained from $HoMnO_3$ thin films post-annealed at $850^{\circ}C$ for 5 min, while the c-axis preferred orientation was decreased with the increase of post-annealing time, and the thin films post-annealed at $850^{\circ}C$ for 15 min showed the mixture phases of hexagonal and orthorhombic symmetry. P-E (Polarization-Electric field) hysteresis loop of ferroelectric $HoMnO_3$ thin films was observed only for the single phase of hexagonal symmetry, but that was not observed for the mixture phases of the hexagonal and orthorhombic symmetry, which was discussed with the bond valence of Mn ion of crystalline phase. Leakage current density was dependent on the microstructure of thin films as well as the change of valence of Mn ion.

A Study on C-axis Preferred Orientation of ZnO Thin Film at Ar/$O_2$gas ratios (Ar/$O_2$에 따른 ZnO 박막의 C-축 배향성에 관한 연구)

  • Lee, Dong-Yoon;Park, Yong-Wook;Nam, Sahn;Lee, Jeon-Kook;Kim, Hyun-Jai;Yoon, Seok-Jin;Whang, Keum-Chan
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.13 no.7
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    • pp.617-624
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    • 2000
  • Zinc Oxide(ZnO) thin films on Si(100) substrate were deposited by RF magnetron reactive sputtering. The charcteristics of ZnO thin films on argon/oxygen(Ar/O$_2$)gas ratios RF power and substrate temperature were investigated by XRD, SEM, and AFM analyses. C-axis preferred orientation resistivity and surface roughness highly depended on Ar/O$_2$gas ratios. The resistivity of ZnO thin films rapidly increased with increasing oxygen ratio and the resistivity value of 9$\times$10$^{7}$ $\Omega$cm was obtained at a working pressure of 10 mTorr with Ar/O$_2$=50/50. The surface roughness was also improved with increasing oxygen ratio and the ZnO films deposited with Ar/O$_2$=50/50 showed the excellent roughness value of 28.7$\AA$.

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A Study of the Crystallographic Characteristic of ZnO Thin Film Grown on ZnO Buffer Layer (ZnO Buffer Layer에 의한 ZnO 박막의 결정학적 특성에 관한 연구)

  • 금민종;손인환;이정석;신성권;김경환
    • Journal of the Korean Vacuum Society
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    • v.12 no.4
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    • pp.214-217
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    • 2003
  • In this study, we prepared ZnO thin film on $SiO_2$/Si substrate by FTS (Facing Targets Sputtering) apparatus which can reduce damage on the thin film because the bombardment of high-energy Particles such as ${\gamma}$-electron can be restrained. And, properties of thin filnl grown with ZnO buffer-layer which can be suppress initial growth layer was investigated. The crystalline and the c-axis preferred orientation of ZnO thin film was also investigated by XRD. As a result, we noticed that the ZnO thin film has a good crystallographic characteristic at thickness of ZnO buffer layer 10, 20 nm and working pressure 1 mTorr.

Preparation of AIN piezoelectric thin film for filters (필터용 AIN 압전 박막의 제작)

  • Keum Min-Jong;Kim Yeong-Cheol;Seo Hwa-Il;Kim Kyung-Hwan
    • Journal of the Semiconductor & Display Technology
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    • v.5 no.1
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    • pp.13-16
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    • 2006
  • AIN thin films were prepared on amorphous glass and $SiO_2(1{\mu}m)/Si(100)$ substrate by the facing targets sputtering (FTS) apparatus, which can provide high density plasma, a high deposition rate at a low working gas pressure. The AIN thin films were deposited at a different nitrogen gas flow rate ($1.0{\sim}0.3$) and other sputtering parameters were fixed such as sputtering power of 200w, working pressures of 1mTorr and AIN thin film thickness of 800 nm, respectively. The thickness and crystallographic characteristics of AIN thin films as a function of $N_2$ gas flow rate $[N_2/(N_2+Ar)]$ were measured by $\alpha$-step and an X-ray diffraction (XRD) instrument. And the c-axis preferred orientations were evaluated by rocking curve. In the results, we could prepared the AIN thin film with c-axis preferred orientation of about $5^{\circ}$ on substrate temperature R.T. at nitrogen gas flow rate 0.7.

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Constructional Characteristics and Propagation Conditions on ZnO Films by Sputtering (스퍼터링에 의한 산화아연박막의 구조적 특성 및 전파경계조건)

  • Lee, Dong-Yoon
    • Proceedings of the Korea Contents Association Conference
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    • pp.807-809
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    • 2009
  • Thin film deposition methods have been widely used and intensively investigated because high quality crystalline films enable to fabricate by sputtering. Especially rf magnetron sputtering deposition has advantages of being employ a relatively high deposition rate and also to achieve high crystalline films in low pressure because plasma density around target by magnetic is high. To apply ZnO thin film for SAW filter, it has highly flat surface, excellent c-axis preferred orientation and high resistivity value. As-deposited ZnO films showed the strong c-axis growth and excellent crystallinity. C-axis preferred orientation, resistivity and surface roughness highly depended on oxygen/argon gas ratio.

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Electrical Characteristics of ZnO Piezo-electric Thin film for SAW filter (SAW 필터용 ZnO 압전 박막의 전기적 특성)

  • Lee, Dong-Yoon;Yoon, Seok-Jin
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.10
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    • pp.909-916
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    • 2005
  • The structural and electrical property of RF magnetron sputtered ZnO thin film have been studied as a function of RF power, substrate temperature, oxygen/argon gas ratio and film thickness at constant sputtering power, sputtering working pressure and target-substrate distance. To analyze a crystallo-graphic properties of the films, $\theta$/2$\theta$ mode X-ray diffraction, SEM, and AFM analyses. C-axis preferred orientation, resistivity and surface roughness highly depended on oxygen/argon gas ratio. The resistivity of ZnO thin film(6000 ${\AA}$) rapidly increased with increasing oxygen ratio and the resistivity value of $9 {\ast} 10^7 {\Omega}cm$ was obtained at a working pressure of 10 mTorr with the same oxygen/argon gas ratio. The surface roughness was also improved with increasing oxygen ratio and the ZnO films deposited with the same oxygen/argon gas ratio showed the excellent roughness value of 28.7 ${\AA}$. With increase of the substrate temperature, The C-axis preferred orientation of ZnO thin film increases and the resistivity decreases due to deviation from the stoichiometric ZnO due to oxygen deficiency.