• Title/Summary/Keyword: underlayer

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Dependence of Magnetoresistance on the Underlayer Thickness for Top-type Spin Valve (Top형 스핀밸브 구조의 Si 기판에서의 하지층 두께에 따른 자기저항 특성 연구)

  • Ko, Hoon;Kim, Sang-Yoon;Kim, Soo-In;Lee, Chang-Woo;Kim, Ji-Won;Jo, Soon-Chul
    • Journal of the Korean Magnetics Society
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    • v.17 no.2
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    • pp.95-98
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    • 2007
  • In this paper, the magnetic properties and the annealing behavior of spin valve structures with Mo(MoN) underlayers were studied for various underlayer thickness. The spin valve structure was Si substrate/Mo(MoN)$(t{\AA})/NiFe(21{\AA})/CoFe(28{\AA})/Cu(22{\AA})/CoFe(18{\AA})/IrMn(65{\AA})/Ta(25 {\AA})$. Mo and MoN films were deposited on Si substrates and their thermal annealing behavior was analyzed. The deposition rate of the MoN thin film was decreased and tile resistivity of the MoN thin films were increased as the $N_2$ gas flow was increased. The variations of MR ratio and magnetic exchange coupling field of spin valve structure were smaller with MoN underlayers than that with Mo underlayers up to thickness of $51{\AA}$. MR ratio of spin valves with Mo underlayers was 2.86% at room temperature and increased up to 2.91 % after annealing at $200^{\circ}C$. Upon annealing at $300^{\circ}C$, the MR ratio decreased about 2.16%. The MR ratio of spin valves structure with MoN underlayers for $N_2$ gas flow 1 sccm was 5.27% at room temperature and increased up to 5.56% after annealing at $200^{\circ}C$. Upon annealing at $300^{\circ}C$, the MR ratio decreased about 4.9%.

Exchange coupling of Co/NiMn bilayer (Co/NiMn의 교환 자기결합에 관한 연구)

  • 안동환;조권구;주승기
    • Journal of the Korean Magnetics Society
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    • v.10 no.4
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    • pp.171-177
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    • 2000
  • Exchange coupling of Co/NiMn bilayers fabricated by RF magnetron sputtering method was studied. We investigated the variation of exchange coupling field (H$\sub$ex/) for different annealing temperature and time. The maximum exchange coupling field was obtained after 13hr annealing at 300 $^{\circ}C$. With respect to deposition sequence, it was demonstrated that NiMn-top bilayers had higher exchange coupling field than NiMn-bottom bilayers. Ta capping layer was shown to be essential in achieving exchange coupling and Auger Electron Spectroscopy (AES) proved that uncapped NiMn/Co bilayers did not have exchange coupling because of oxygen incorporation into film. We also observed the effect of Ta underlayer on exchange coupling. It was found that Ta underlayer had better not be used for attaining higher exchange coupling. XRD analysis showed that Ta underlayer helped bilayers develop texture, but it was not essential to exchange coupling of Co/NiMn bilayers, which is in contrast to NiFe/NiMn system. Furthermore, the NiMn and Co thickness dependence of exchange coupling has been investigated. The exchange coupling strength reached the maximum above 200 ${\AA}$ NiMn thickness and had inversely proportional relation with Co thickness.

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Shielding effect model and Signal Switching in the multi-layer interconnects (다층 배선에서 차폐효과 모델 및 스위칭에 미치는 영향)

  • 진우진;어영선
    • Proceedings of the IEEK Conference
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    • 1998.10a
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    • pp.1145-1148
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    • 1998
  • New capacitance modeling and transient analysis for multi-layer interconnects with shielding effect are presented. The upper layer capacitances with under-layer shielding lines are represented by introducing a filling factor η which can be defined as the ratio of upper-layer line length to the total under-layer line width. The upper-layer effective self capacitances considering two extreme cases which the underlayer metals are assumed as a ground or as a Vdd are modeled. The signal transient analysis with shielding effect model is performed.

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A Study on Diffusion Behavior in NiFe/Ag Bilayer Films deposited by ion Beam Sputtering Methods (이온빔 스퍼터링 방법으로 증착한 NiFe/Ag 박막의 확산 거동)

  • 지재범;이성래;문대원
    • Journal of the Korean institute of surface engineering
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    • v.35 no.2
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    • pp.107-112
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    • 2002
  • We have studied diffusion behavior of NiFe/Ag bilayer deposited by on silicon Ion Beam Sputtering methods. The diffusion behavior of NiFe and Ag in NiFe/Ag thin film is analyzed by Medium Energy Ion Scattering Spectroscopy. For samples without Ta underlayer, silicides such as Ni-Si or Fe-Si were formed at Si substrate and NiFe interface. In contrast, Ag predominantly diffused into the NiFe layer probably through their grain boundaries for Ta underlayered samples.