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Thermal stability of nanoscale silver metallization in Ag/W/Co/Si(1 0 0) multilayer

Akhavan, O ; Sharif University of Technology | 2006

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  1. Type of Document: Article
  2. DOI: 10.1016/j.apsusc.2005.12.070
  3. Publisher: Elsevier , 2006
  4. Abstract:
  5. In this work, we have studied thermal stability of nanoscale Ag metallization and its contact with CoSi 2 in heat-treated Ag(50 nm)/W(10 nm)/Co(10 nm)/Si(1 0 0) multilayer fabricated by sputtering method. To evaluate thermal stability of the systems, heat-treatment was performed from 300 to 900 °C in an N 2 ambient for 30 min. All the samples were analyzed by four-point-probe sheet resistance measurement (R s ), Rutherford backscattering spectrometry (RBS), X-ray diffractometry (XRD), and atomic force microscopy (AFM). Based on our data analysis, no interdiffiusion, phase formation, and R s variation was observed up to 500 °C in which the Ag layer showed a (1 1 1) preferred crystallographic orientation with a smooth surface and R s of about 1 Ω/□. At 600 °C, a sharp increase of R s value was occurred due to initiation of surface agglomeration, WSi 2 formation, and interdiffusion between the layers. Using XRD spectra, CoSi 2 formed at the Co/Si interface preventing W silicide formation at 750 and 800 °C. Meantime, RBS analysis showed that in this temperature range, the W acts as a cap layer, so that we have obtained a W encapsulated Ag/CoSi 2 contact with a smooth surface. At 900 °C, the CoSi 2 layer decomposed and the layers totally mixed. Therefore, we have shown that in Ag/W/Co/Si(1 0 0) multilayer, the Ag nano-layer is thermally stable up to 500 °C, and formation of W-capped Ag/CoSi 2 contact with R s of 2 Ω/□ has been occurred at 750-800 °C. © 2005 Elsevier B.V. All rights reserved
  6. Keywords:
  7. Atomic force microscopy ; Crystallography ; Heat treatment ; Metallizing ; Multilayers ; Rutherford backscattering spectroscopy ; Sputtering ; Thermodynamic stability ; X ray diffraction ; Co silicide ; Interdiffusion ; Nano-metallization ; W interlayer ; Silver
  8. Source: Applied Surface Science ; Volume 252, Issue 15 , 2006 , Pages 5335-5338 ; 01694332 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S016943320501665X