Titanium deposition onto copper substrates using the cold-plasma technique

Abstract

Titanium coatings were deposited onto copper substrates using the r.f. cold-plasma technique. The coatings were obtained from gas mixtures of TiCl 4H 2Ar. The substrate temperature was 550°C and the total gas pressure in the reactor was 2 mbar. The plasma was sustained by an r.f. generator of 27 MHz frequency at a power of about 650 W. Scanning electron microscopy, X-ray diffraction, transmission electron microscopy (TEM) and Auger electron spectroscopy were employed to identify and to characterize the coatings obtained. Coatings of thickness 10 μm were obtained after 5 h of deposition. The coatings were found to be slightly porous. Energy-dispersive analysis of X-rays was employed along the cross section of the coatings and the results indicate that titanium and copper compose the coating in varying concentrations. Chlorine impurities were found to constitute less than 0.5%. X-ray diffraction and TEM selected area diffraction revealed the presence of a mixture of various TiCu intermetallic compounds which compose the coating. Pure crystalline titanium was not observed.