• Title/Summary/Keyword: multilayer structure

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A Study on the High Frequency Characteristics and Equivalent Circuit Model of Microstrip Lines Having Defected Ground Structures in Multilayer Substrates (다층기판으로 구현된 마이크로스트립 선로와 결함접지구조의 초고주파 특성 및 등가회로 모델링)

  • Oh, Seong-Min;Koo, Jae-Jin;Park, Chun-Sun;Hwang, Mun-Su;Ahn, Dal;Lim, Jong-Sik
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.7 no.6
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    • pp.1106-1115
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    • 2006
  • In this paper, the transmission characteristics and equivalent circuit model of microstrip transmission line having defected ground structure (DGS) in multilayer substrates are described fur high frequency region. In order to perform the study, the second dielectric layer is attached additionally onto the bottom(ground) plane of the basic DGS microstrip line consisted of the microstrip line and DGS. The dielectric constant and thickness of the second dielectric layer are adjusted to get various transmission characteristics and model parameters, and to analysis the effect of the second dielectric layer ultimately. According to this paper, the effect and equivalent circuits due to the attached dielectric substrate are verified separately, and this is expected to be applied to high frequency circuit design in the future.

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The Effects of ZnO Sub-layer Thickness on the Room Temperature Ferromagnetism of (ZnO/Co) Multilayer ((ZnO/Co) 다층 박막에서 ZnO층의 두께가 상온강자성 특성에 미치는 영향)

  • Kang, Sung-geun;Kim, Sungdong
    • Journal of the Microelectronics and Packaging Society
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    • v.25 no.4
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    • pp.137-142
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    • 2018
  • Room temperature ferromagnetism of Co doped ZnO was studied using (ZnO/Co) multilayer structure, and the effects of ZnO sub-layer thickness on the RT ferromagnetism was investigated. As for the as-deposited state, the diamagnetism was observed for ($ZnO\;20{\AA}/Co\;x{\AA}$) while the ferromagnetism was observed for ($ZnO\;40{\AA}/Co\;x{\AA}$). After vacuum-annealed, both showed the RT ferromagnetism and ($ZnO\;40{\AA}/Co\;x{\AA}$) structure interestingly showed negative remanence magnetization behavior. UV-Vis spectrometer revealed that Co atoms were substituted with Zn in ZnO and Co cluster was not found in XPS and HRTEM EDS analysis.

A Study on the Design and Fabrication of GHz Magnetic Thin Film Inductor Utilizing Co90Fe10/SiO2 Multilayer (Co90Fe10/SiO2 Multilayer를 이용한 GHz 자성박막 인덕터 설계 및 제작에 관한 연구)

  • 공기준;윤의중;진현준;박노경;문대철
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.5B
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    • pp.985-991
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    • 2000
  • In this paper, the optimum structure of 2GHz magnetic thin film planar inductor were designed and fabricated to reduce the inductor area and to maximize the inductance L and quality factor Q of the inductor. The optimum design was performed utilizing Co90Fe10 layer multilayered with SiO2 layers to avoid the eddy-current skin effect and considering new lumped element model. New magnetic thin film inductors operating at 2GHz were fabricated on a Si substrate utilizing photo-lithography and lift-off techniques. The frequency characteristics of L, Q, and impedance in more than fifty identical inductors were measured using an RF Impedance Analyzer(HP4291B with HP16193A test fixture). The self-resonant frequencies(SRF) of the inductors were measured by a Vector Network Analyzer(HP8510). The developed inductors have SRF of 1.8 to 2.3GHz, L of 47 to 68nH, and Q of 70 to 80 near 1GHz. Finally, high frequency, high performance, planar micro-inductor(area=30.8 x 30.8il$^2$) with maximized L and Q were fabricated succefully.

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Fabrication and Electrical Properties of PZT/BFO Multilayer Thin Films

  • Jo, Seo-Hyeon;Nam, Sung-Pil;Lee, Sung-Gap;Lee, Seung-Hwan;Lee, Young-Hie;Kim, Young-Gon
    • Transactions on Electrical and Electronic Materials
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    • v.12 no.5
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    • pp.193-196
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    • 2011
  • Lead zirconate titanate (PZT)/ bismuth ferrite (BFO) multilayer thin films have been fabricated by the spin-coating method on Pt(200 nm)/Ti(10 nm)/$SiO_2$(100 nm)/p-Si(100) substrates using $BiFeO_3$ and $Pb(Zr_{0.52}Ti_{0.48})O_3$ metal alkoxide solutions. The PZT/BFO multilayer thin films show a uniform and void-free grain structure, and the grain size is smaller than that of PZT single films. The reason for this is assumed to be that the lower BFO layers play an important role as a nucleation site or seed layer for the formation of homogeneous and uniform upper PZT layers. The dielectric constant and dielectric losses decreased with increasing number of coatings, and the six-layer PZT/BFO thin film has good properties of 162 (dielectric constant) and 0.017 (dielectric losses) at 1 kHz. The remnant polarization and coercive field of three-layer PZT/BFO thin films were 13.86 ${\mu}C/cm^2$ and 37 kV/cm respectively.

Hydrogen-Bonding Induced Alternating Thin Films of Dendrimer and Block Copolymer Micelle

  • Park, Chi-Young;Rhue, Mi-Kyo;Im, Min-Ju;Kim, Chul-Hee
    • Macromolecular Research
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    • v.15 no.7
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    • pp.688-692
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    • 2007
  • The hydrogen-bonding induced alternating multilayer thin films of dendrimers and block copolymer micelles were demonstrated. The block copolymer micelles derived from amphiphilic poly(2-ethyl-2-oxazoline)block-$poly({\varepsilon}-carprolactone)$ (PEtOz-PCL) in aqueous phase have a core-shell structure with a mean hydrodynamic diameter of 26 nm. The hydrogen bonding between the PEtOz outer shell of micelle and the carboxyl unit of poly(amidoamine) dendrimer of generation 4.5 (PAMAM-4.5G) at pH 3 was utilized as a driving force for the layerby-layer alternating deposition. The multilayer thin film was fabricated on the poly(methyl methacrylate) (PMMA) thin film spin-coated on silicon wafer or glass substrate by the alternate dipping of PEtOz-PCL micelles and PAMAM dendrimers in aqueous solution at pH 3. The formation of multilayer thin film was characterized by using ellipsometry, UV-vis spectroscopy, and atomic force microscopy. The PEtOz outer shell of PEtOz-PCL micelle provided the pH-responsive hydrogen bonding sites with peripheral carboxylic acids of PAM AM dendrimer. The multilayer thin film was reversibly removed after dipping in aqueous solution at $pH{\geq}5.6$ due to dissociation of the hydrogen bonding between PEtOz shell of PEtOz-PCL micelle and peripheral carboxyl units of PAMAM dendrimer.

Preparation and Properties of Poly(vinylidene fluoride) Multilayer Films (Poly(vinylidene fluoride) 다층 필름의 제조 및 특성)

  • Son, Tae-Won;Kim, Jong-Hwan;Choi, Won-Mi;Han, Fei-Fei;Kwon, Oh-Kyeong
    • Polymer(Korea)
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    • v.35 no.2
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    • pp.130-135
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    • 2011
  • Along with the fast development of electronics, the demands of portable electronics and wireless sensors are growing rapidly. The need for self-powering materials capable of powering the electrical devices attached to them is increasing, The piezoelectric effect of polyvinylidene fluoride (PVDF) can be used for this purpose. PVDF has a special crystal structure consisting of a ${\beta}$-phase that can produce piezoelectricity. In this paper, multilayer PVDF films were fabricated to increase the ${\beta}$-phase content. A solution of 10% concentration N;N-dimethylacetamide (DMAc) in PVDF (PVDF/DMAc) was used to fabricate the films via spin coating technique with the following optimum process parameters: a spin rate of 850 rpm, spin time of 60 s, drying temperature of $60^{\circ}C$, and drying time of 30 min, Compared with single-layer PVDF films, the multilayer films exhibited higher ${\beta}$-phase content. The ${\beta}$-phase content of the films increased gradually with increasing number of layers until 4, Maximum ratio of ${\beta}$-phase content was 7.72.