Interdiffusion in composition‐modulated copper‐gold thin films

Vapor‐deposited Cu‐Au thin films were produced containing composition modulations with wavelengths between 8 and 26 A. The modulations produced satellite peaks in the x‐ray diffraction patterns. Amplification factors and the corresponding diffusion coefficients were obtained by measuring the decay rate of the satellite intensities. The amplification factor reached a maximum at 17 A and decreased at both shorter and longer wavelengths. Interdiffusion coefficients between 10−21 and 10−19 cm2/sec were measured over the temperature range 200–260 °C. The effective diffusion coefficient is linearly dependent on the function B2(λ) for λ≳10 A. From the wavelength dependence of the measured diffusivities, a gradient‐energy coefficient of −4.7×10−6 erg/cm was obtained and is in good agreement with theoretical estimates. These experimental results were compared with the predictions from a proposed model for diffusion on cubic lattices.

[1]  H. E. Cook,et al.  A model for diffusion on cubic lattices and its application to the early stages of ordering , 1969 .

[2]  John W. Cahn,et al.  On Spinodal Decomposition , 1961 .

[3]  W. B. Pearson,et al.  A handbook of lattice spacings and structures of metals and alloys , 1958 .

[4]  J. E. Hilliard,et al.  LOCAL ATOMIC ARRANGEMENTS STUDIED BY X-RAY DIFFRACTION. Proceedings of a Symposium held in Chicago, Illinois, February 15, 1965. , 1966 .

[5]  B. S. Berry,et al.  X‐ray study of interdiffusion in bimetallic Cu–Au films , 1972 .

[6]  J. DuMond,et al.  An X-Ray Method of Determining Rates of Diffusion in the Solid State , 1940 .

[7]  H. E. Cook,et al.  Brownian motion in spinodal decomposition , 1970 .

[8]  Paul Shewmon,et al.  Diffusion in Solids , 2016 .

[9]  John W. Cahn,et al.  On spinodal decomposition in cubic crystals , 1962 .

[10]  S. U. Campisano,et al.  Low temperature interdiffusion in copper-gold thin films analysed by helium back-scattering , 1973 .

[11]  E. Philofsky,et al.  Effect of Coherency Strains on Diffusion in Copper‐Palladium Alloys , 1969 .

[12]  J. Cohen,et al.  Increasing the Versatility of the G. E. Diffractometer , 1963 .

[13]  D. Fabian,et al.  Lattice and grain-boundary diffusion of gold in Copper , 1969 .

[14]  H. B. Huntington.  The Elastic Constants of Crystals , 1958 .

[15]  F. Asaro,et al.  Diffusion of Gold into Copper , 1954 .

[16]  J. Borders.  Ion back-scattering analysis of interdiffusion in Cu-Au thin films , 1973 .

[17]  D. Fontaine,et al.  On the elastic free energy of solid solutions—II. Influence of the effective modulus on precipitation from solution and the order-disorder reaction , 1971 .

[18]  M. Hansen,et al.  Constitution of Binary Alloys , 1958 .

[19]  S. Siegel.  The Variation of the Principal Elastic Moduli ofCu3Au with Temperature , 1940 .

[20]  R. A. Oriani.  Thermodynamics of ordering alloys, II. The gold-copper system , 1954 .

[21]  S. Mader,et al.  Metastable evaporated thin films of CuAg and CoAu alloys—I occurrence and morphology of phases , 1967 .

[22]  W. C. Overton,et al.  Temperature Variation of the Elastic Constants of Cubic Elements. I. Copper , 1955 .

[23]  A. E. Austin,et al.  Grain‐Boundary Diffusion of Gold in Copper , 1962 .

[24]  J. E. Hilliard,et al.  Effect of Gradient Energy on Diffusion in Gold‐Silver Alloys , 1969 .