Surface self‐diffusion measurements on copper

The decay kinetics of sinusoidal surface profiles on copper annealed in a hydrogen atmosphere were investigated in the temperature range 600 to 1030 °C in order to determine the temperature dependence of the surface self‐diffusion coefficient, D s . Below 910 °C the surface profiles were found to be faceted resulting in an apparent discontinuity in D s which can be understood in terms of the γ‐plot of copper. The discontinuity in the diffusion data can be expressed by the following equations:At temperatures below 800 °C is dependent on the annealing time, and inthe vicinity of 600 °C, D s drops drastically below the minimumvalue that can be measured. This behavior can be explained in terms of the rate theory for a bimolecular surface reation between impurities and diffusing defects. From the predicted time dependence of D s , it is possible to estimate D s at t=0. These D s −values are greater than the extrapolated high temperature data, thus indicating thepossibility of a lower activation energy for surface self‐diffusion at low temperatures.