Ion scattering spectroscopy was used to determine surface concentrations after sputtering. The diffusivity of O-free high-conductivity Cu was described by:

D (cm2/s) = 3.3 x 10-1 exp[-49.4(kcal/mol)/RT]

J.W.Pugh, R.F.Hehemann, D.J.Diederich: Metallurgical Transactions A, 1980, 11[12], 2036-8