Surface and structural disorder in MBE and sputtering deposited Cu thin films revealed by X-ray measurements

Copper thin films have been deposited on Si substrates by molecular beam epitaxy (MBE) at different deposition rates varying from 1 up to 22 Å/s. X-ray reflectivity and θ–2θ measurements have shown that the surface roughness correlation length, the structural disorder and the grain dimensions are strongly affected by the deposition rate. Comparing these results with those obtained for sputtered deposited thin films with a low deposition rate (2.5 Å/s), a clear similarity between the MBE samples deposited with the highest deposition rate and the sputtering Cu films is observed. This result has been interpreted considering the different energies of the particles that approach the substrate in the two deposition techniques.