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Effect of annealing on the mechanical behaviour of Au/Cu and Cu/Au bilayers on silicon
Author(s) -
Chocyk D.,
Prószyński A.,
Gladyszewski G.
Publication year - 2010
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.201000362
Subject(s) - annealing (glass) , silicon , materials science , copper , atmospheric temperature range , analytical chemistry (journal) , metal , thermal expansion , composite material , crystallography , metallurgy , chemistry , thermodynamics , physics , chromatography
The realtime evolution of stress during deposition of Cu/Au and Au/Cu bilayers was studied by an in‐situ curvature measurement optical technique and annealing in the temperature range from room temperature to 400 °C. The Au/Cu and Cu/Au bilayers attached to silicon substrate with total thickness equal 12 nm and individual film thicknesses equal 6 nm Cu and 6 nm Au; 4 nm Cu and 8 nm Au; and 8 nm Cu and 4 nm Au, respectively, were examined. During deposition, an increase in tensile stress with increasing the total thickness of a system for both Au/Cu and Cu/Au bilayers were observed. Deposition of Au layer on Cu layer resulted in a change in compressive direction, whereas no change was observed for Cu deposition on Au. This difference is explained by lattice parameter mismatch. Significant stress evolution during the first cycle of heating was observed for all samples. It was found that irreversible modifications occur in systems during the first cycle of annealing. A change in the slope of the elastic part of stress curve during heating indicates a change in the coefficient of thermal expansion of metallic layers. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)