• 제목/요약/키워드: Fe thin film

검색결과 635건 처리시간 0.039초

Fe93.5Si6.5 자성분말/에폭시 복합재 필름의 고주파 특성 (High Frequency Properties of Fe93.5Si6.5 Magnetic Powder/Epoxy Composite Film)

  • 홍성민;김철기
    • 한국자기학회지
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    • 제18권5호
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    • pp.195-199
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    • 2008
  • $Fe_{93.5}Si_{6.5}$ 분말/에폭시 복합재 필름은 열경화과정을 이용하여 준비되었다. 자성분말/에폭시 복합재의 구조와 전자기적 특성 및 전자파 흡수특성을 분석하기 위하여 주사전자현미경(scanning electron microscpoe, SEM), 시료진동형 자력계(vibrating sample magnetometer, VSM), 네트워크 어날라이져(network analyzer) 등을 이용하였다. 분석결과, 포화자속밀도는 복합재 내의 $Fe_{93.5}Si_{6.5}$ 분말이 차지하는 양에 의존하며, 이는 초기투자율에 영향을 미친다. 결과적으로 1 GHz 이상의 주파수에서는 와전류 손실(eddy current loss)이 주요한 인자이며, 자성분말/에폭시 복합재의 공명주파수(resonance frequency)는 복합재 내의 $Fe_{93.5}Si_{6.5}$ 분말의 양이 증가함에 따라 감소한다. 반사손실(reflection loss)은 자성분말/에폭시 복합재의 투자율(permeability)과 유전율(permittivity)로부터 계산에 의해 구해진다. 50 wt% $Fe_{93.5}Si_{6.5}$ 분말의 양과 5 mm 두께를 가진 자성분말/에폭시 복합재는 3.66 GHz와 4.16 GHz 사이에서 -20 dB 이하의 값을 보인다. 따라서 Fe-Si/에폭시 박형 복합재는 마이크로파 흡수체로서 좋은 후보물질이 될 수 있을 것으로 판단된다.

SiON buffer layer를 이용한 MFIS Capacitor의 제작 및 특성 (Fabrications and properties of MFIS capacitor using SiON buffer layer)

  • 정상현;정순원;인용일;김광호
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 하계학술대회 논문집
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    • pp.70-73
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    • 2001
  • MFIS(Metal-ferroelectric-insulator- semiconductor) structures using silicon oxynitride(SiON) buffer layers were fabricatied and demonstrated nonvolatile memory operations. Oxynitride(SiON) films have been formed on p-Si(100) by RTP(rapid thermal process) in O$_2$+N$_2$ ambient at 1100$^{\circ}C$. The gate leakage current density of Al/SiON/Si(100) capacitor was about the order of 10$\^$-8/ A/cm$^2$ at the range of ${\pm}$ 2.5 MV/cm. The C-V characteristics of Al/LiNbO$_3$/SiON/Si(100) capacitor showed a hysteresis loop due to the ferroelectric nature of the LiNbO$_3$ thin films. Typical dielectric constant value of LiNbO$_3$ film of MFIS device was about 24. The memory window width was about 1.2V at the electric field of ${\pm}$300 kV/cm ranges.

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Electrical Properties of Ferroelectric Polymer on Inorganic Dielectric Layer for FRAM

  • Han, Hui-Seong;Kim, Kwi-Jung;Jeon, Ho-Seung;Park, Byung-Eun
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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    • pp.258-258
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    • 2008
  • Among several available high-k dielectrics the lanthanum zirconium oxide ($LaZrO_x$) system is very attractive as a buffer insulating layer. Because both lanthanum and zirconium atoms, the constituents of the $LaZrO_x$ thin film, have been considered to be thermally stable in contact with Si. The $LaZrO_x$ films were deposited by a sol-gel method. After the deposition, The $LaZrO_x$ films were crystallized at $750^{\circ}C$ for 30 minutes in $O_2$ ambient. PVDF-TrFE films were deposited on these $LaZrO_x$/Si structures using a sol-gel technique. The sol-gel solution was spin-coated on $LaZrO_x$/Si structures at 500 rpm for 5 sec and 2500 rpm for 15 sec. The deposited layer was dried at $165^{\circ}C$ for 30 min in air on a hot-plate. Then, we deposited Au electrode on PVDF-TrFE films using thermal evaporation.

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Nonvolatile Ferroelectric P(VDF-TrFE) Memory Transistors Based on Inkjet-Printed Organic Semiconductor

  • Jung, Soon-Won;Na, Bock Soon;Baeg, Kang-Jun;Kim, Minseok;Yoon, Sung-Min;Kim, Juhwan;Kim, Dong-Yu;You, In-Kyu
    • ETRI Journal
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    • 제35권4호
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    • pp.734-737
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    • 2013
  • Nonvolatile ferroelectric poly(vinylidene fluoride-co-trifluoroethylene) memory based on an organic thin-film transistor with inkjet-printed dodecyl-substituted thienylenevinylene-thiophene copolymer (PC12TV12T) as the active layer is developed. The memory window is 4.5 V with a gate voltage sweep of -12.5 V to 12.5 V. The field effect mobility, on/off ratio, and gate leakage current are 0.1 $cm^2/Vs$, $10^5$, and $10^{-10}$ A, respectively. Although the retention behaviors should be improved and optimized, the obtained characteristics are very promising for future flexible electronics.

동시 스퍼터링법에 의한$Pb(Fe^{0.5},Nb^{0.5}O_3$박막의 제조 및 특성 평가에 대한 연구 (A study on the fabrication of $Pb(Fe^{0.5},Nb^{0.5}O_3$ thin films by a Co-sputtering technique and their characteristics properties)

  • 이상욱;신동석;최인훈
    • 한국진공학회지
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    • 제7권1호
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    • pp.17-23
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    • 1998
  • RF magnetron co-sputtering법으로 PFN[$Pb(Fe_{0.5}Nb_{0.5}O_3(PFN)$]박막을 제조한 후 급속 열처리(rapid thermal annealing, RTA)하여 XRD(s-ray diffractometer)를 통한 박막의 상변 태 및 전기적 특성에 대하여 연구하였다. $SiO_2$/Si, ITO/glass, 및 Pt/Ti/$SiO_2$/Si기판에 PFN 박막을 증착시켰다. 기판의 변화에 따른 증착된 PFN박막의 조성변화는 관찰할 수 없었다. ITO/glass기판을 사용한 경우와 $SiO_2$/Si기판을 사용하여 증착시킨 PFN박막의 결정구조를 분석한 결과 ITO/glass기판에 증착한 시편이 perovskite상으로의 결정화가 더욱 우세하였다. 이는$SiO_2$기판의 경우 Pb의 확산에 의해 결정화가 잘 되지 못하기 때문이다. Pt/Ti/$SiO_2$/Si 기판 위에 증착시킨 PFN박막의 경우 perovskite상과 pyrochlore상이 공존하였다. Perovskite 상으로의 상변태에 대한 중요한 변수로는 열처리 온도와 Pb의 함량인 것이 확인되었으며, Pb의 함량이 화학양론적 조성비에 비해 5-10%정도 과량일수록 perovskite상으로의 상변태 온도가 낮아지고 상전이 정도가 향상되는 것으로 나타났으며, 급속 열처리 후 XRD를 이용 한 결정성 분석결과를 통해 결정한 perovskite상으로의 상전이 최저온도는 $500^{\circ}C$였다. Pb/(Fe+Nb)의 조성비가 1.17인 경우의 박막을 질소 분위기 하에서 $600^{\circ}C$로 30초간 급속열 처리 하였을 때 낮은 누설 전류 값과 1kHz에서 88의 유전 상수 값, 2.0$\mu$C/$\textrm{cm}^2$의 잔류 분극 값과 144kV/cm의 항전계 값을 얻었다.

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구리 박막의 기계적 물성 평가 및 유한요소 해석 (Evaluation of Mechanical Properties and FEM Analysis on Thin Foils of Copper)

  • 김윤재;안중혁;박준협;김상주;김영진;이영제
    • Tribology and Lubricants
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    • 제21권2호
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    • pp.71-76
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    • 2005
  • This paper compares of mechanical tensile properties of 6 kinds of copper foil. The beam lead made with copper foil. Different from other package type such as plastic package, Chip Size Package has a reliability problem in beam lead rather than solder joint in board level. A new tensile loading system was developed using voice-coil actuator. The new tensile loading system has a load cell with maximum capacity of 20 N and a non-contact position measuring system based on the principle of capacitance micrometry with 0.1nm resolution for displacement measurement. Strain was calculated from the measured displacement using FE analysis. The comparison of mechanical properties helps designer of package to choose copper for ensuring reliability of beam lead in early stage of semiconductor development.

Heteroepitaxial Structure of ZnO Films Deposited on Graphene, $SiO_2$ and Si Substrates

  • Pak, Sang-Woo;Cho, Seong-Gook;Kim, Eun-Kyu
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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    • pp.309-309
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    • 2012
  • Heteroepitaxial growth remains as one of the continuously growing interests, because the heterogeneous crystallization on different substrates is a common feature in the fabrication processes of many semiconductor materials and devices, such as molecular beam epitaxy, pulsed laser deposition, sputtering, chemical bath deposition, chemical vapor deposition, hydrothermal synthesis, vapor phase transport and so on [1,2]. By using the R.F. sputtering system, ZnO thin films were deposited on graphene 4 and 6 mono layers, which is grown on 400 nm and 600 nm $SiO_2$ substrates, respectively. The ZnO thin layer was deposited at various temperatures by using a ZnO target. In this experimental, the working power and pressure were $3{\times}10^{-3}$ Torr and 50 W, respectively. The base pressure of the chamber was kept at a pressure around $10^{-6}$ Torr by using a turbo molecular pump. The oxygen and argon gas flows were controlled around 5 and 10 sccm by using a mass flow controller system, respectively. The structural properties of the samples were analyzed by XRD measurement. The film surface and carrier concentration were analyzed by an atomic force microscope and Hall measurement system. The surface morphologies were observed using field emission scanning electron microscope (FE-SEM).

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Influence of surface morphology and thickness of molecular thin films on the performance of SubPc-$C_{60}$ photovoltaic devices

  • Kim, Jin-Hyun;Gong, Hye-Jin;Yim, Sang-Gyu
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2011년도 제40회 동계학술대회 초록집
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    • pp.336-336
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    • 2011
  • Over the past decades, organic semiconductors have been investigated intensely for their potential in a wide range of optoelectronic device applications since the organic materials have advantages for very light, flexible and low cost device fabrications. In this study, we fabricated small-molecule organic solar cells (OSCs) based on chloro[subphthalocyaninato]boron(III) (SubPc) as an electron donor and $C_{60}$ as an electron acceptor material. Recently SubPc, a cone-shaped molecule with $14{\pi}$-electrons in its aromatic system, has attracted growing attention in small-molecule OSC applications as an electron-donating material for its greater open-circuit voltage (VOC), extinction coefficient and dielectric constant compared to conventional planar metal phthalocyanines. In spite of the power conversion efficiency (PCE) enhancement of small-molecule OSC using SubPc and $C_{60}$, however, the study on the interface between donor-acceptor heterojunction of this system is limited. In this work, SubPc thin films at various thicknesses were deposited by organic molecular beam deposition (OMBD) and the evolution of surface morphology was observed using atomic force microscopy (AFM) and field emission scanning electron microscopy (FE-SEM). We also investigated the influence of film thickness and surface morphology on the PCE of small-molecule OSC devices.

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A Review of Epitaxial Metal-Nitride Films by Polymer-Assisted Deposition

  • Luo, Hongmei;Wang, Haiyan;Zou, Guifu;Bauer, Eve;Mccleskey, Thomas M.;Burrell, Anthony K.;Jia, Quanxi
    • Transactions on Electrical and Electronic Materials
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    • 제11권2호
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    • pp.54-60
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    • 2010
  • Polymer-assisted deposition is a chemical solution route to high quality thin films. In this process, the polymer controls the viscosity and binds metal ions, resulting in a homogeneous distribution of metal precursors in the solution and the formation of crack-free and uniform films after thermal treatment. We review our recent effort to epitaxially grow metal-nitride thin films, such as hexagonal GaN, cubic TiN, AlN, NbN, and VN, mixed-nitride $Ti_{1-x}Al_xN$, ternary nitrides tetragonal $SrTiN_2$, $BaZrN_2$, and $BaHfN_2$, hexagonal $FeMoN_2$, and nanocomposite TiN-$BaZrN_2$.

Hf0.5Zr0.5O2 강유전체 박막의 다양한 분극 스위칭 모델에 의한 동역학 분석 (Switching Dynamics Analysis by Various Models of Hf0.5Zr0.5O2 Ferroelectric Thin Films)

  • 안승언
    • 한국재료학회지
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    • 제30권2호
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    • pp.99-104
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    • 2020
  • Recent discoveries of ferroelectric properties in ultrathin doped hafnium oxide (HfO2) have led to the expectation that HfO2 could overcome the shortcomings of perovskite materials and be applied to electron devices such as Fe-Random access memory (RAM), ferroelectric tunnel junction (FTJ) and negative capacitance field effect transistor (NC-FET) device. As research on hafnium oxide ferroelectrics accelerates, several models to analyze the polarization switching characteristics of hafnium oxide ferroelectrics have been proposed from the domain or energy point of view. However, there is still a lack of in-depth consideration of models that can fully express the polarization switching properties of ferroelectrics. In this paper, a Zr-doped HfO2 thin film based metal-ferroelectric-metal (MFM) capacitor was implemented and the polarization switching dynamics, along with the ferroelectric characteristics, of the device were analyzed. In addition, a study was conducted to propose an applicable model of HfO2-based MFM capacitors by applying various ferroelectric switching characteristics models.