Texture and stress of Ag films in Ag/Ti, Ag/Cr bilayers, and selfencapsulated structures

Yuxiao Zeng, Y. L. Zou, T. L. Alford, F. Deng, S. S. Lau, T. Laursen, B. Manfred Ullrich

Research output: Contribution to journalArticle

31 Scopus citations

Abstract

The texture of evaporated Ag films prepared on Ti or Cr underlayers before and after encapsulation process has been studied by x-ray diffraction. In addition, the stress state in self-encapsulated Ag/Ti structures has also been investigated using a "sin2 ψ" technique. Silver films deposited on Ti layers exhibit a strong <111> texture, which is in contrast to the nearly random orientation of Ag films on Cr underlayers. The minimization of interfacial energy with respect to lattice match can account for this underlayer dependence. After an encapsulation process involving Ti reactions in an ammonia ambient, the texture of Ag films in Ag/Ti bilayers is further enhanced. Highly textured Ag films may provide the basis for electromigration-resistant Ag metallization in integrated circuit devices. For the Ag/Ti bilayer structures, a low tensile stress of approximately 61 MPa arising from the nonequilibrium growth during the film deposition is present in the Ag films. This results in a lattice tension state in the film plane and a lattice compression state along the film normal. Thermal mismatch stress is produced by the encapsulation process at 600 °C. Most of this stress relaxes during the cooling stage and a residual tensile stress of ∼320 MPa in the film plane was determined.

Original languageEnglish (US)
Pages (from-to)7773-7777
Number of pages5
JournalJournal of Applied Physics
Volume81
Issue number12
DOIs
StatePublished - Jun 15 1997
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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    Zeng, Y., Zou, Y. L., Alford, T. L., Deng, F., Lau, S. S., Laursen, T., & Manfred Ullrich, B. (1997). Texture and stress of Ag films in Ag/Ti, Ag/Cr bilayers, and selfencapsulated structures. Journal of Applied Physics, 81(12), 7773-7777. https://doi.org/10.1063/1.365386