Korean Journal of Materials Research (한국재료학회지)

Materials Research Society of Korea (한국재료학회)
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Characteristics of Gate Oxides with Cobalt Silicide Process

복합 코발트 실리사이드 공정에 따른 게이트 산화막의 특성변화

  • Song, Oh-sung (Department of Materials Science and Engineering, The University of Seoul) ;
  • Cheong, Seong-hwee (Department of Materials Science and Engineering, The University of Seoul) ;
  • Yi, Sang-don (Department of Materials Science and Engineering, The University of Seoul) ;
  • Lee, Ki-yung (Department of Materials Science and Engineering, The University of Seoul) ;
  • Ryu, Ji-ho (Devision of Machine & Automobile, Daecheon College)
  • 송오성 (서울시립대학교 신소재공학과) ;
  • 정성희 (서울시립대학교 신소재공학과) ;
  • 이상돈 (서울시립대학교 신소재공학과) ;
  • 이기영 (서울시립대학교 신소재공학과) ;
  • 류지호 (대천대학 자동차기계학부)
  • Published : 2003.11.01
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Abstract

Gate length, height, and silicide thickness have all been shrinking linearly as device density has progressively increased over the years. We investigated the effect of the cobalt diffusion during the silicide formation process on the 60$\AA$-thick gate oxide lying underneath the Ti/Co and Co/Ti bilayers. We prepared four different cobalt silicides, which have similar sheet resistance, made from the film structure of Co/Ti(interlayer), and Ti(capping layer)/Co, and peformed the current-voltage, time-to-break down, and capacitance-voltage measurements. Our result revealed that the cobalt silicide process without the Ti capping layer allowed cobalt atoms to diffuse into the upper interface of gate oxides. We propose that 100$\AA$-thick titanium interlayer may lessen the diffusion of cobalt to gate oxides in 1500-$\AA$ height polysilicon gates.

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References

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