Influence of cathode voltage on electrical property and crystal structure of sputter-deposited Ag thin films

The resistivity and crystal structure of Ag thin films were investigated as a function of the cathode voltage during the Ag sputter deposition. Low emissivity (low-e) coatings with a layered construction of glass/dielectric/Ag/dielectric were deposited by magnetron sputtering. It was found that the Ag layers in the low-e coatings showed lower resistivity when lower cathode voltage was applied. Furthermore, the X-ray diffraction measurement revealed that the crystallite of the Ag layer became larger with the decrease of the cathode voltage. It can be seen from these results that the Ag deposition resulting from low cathode voltage contributes to preferred crystal growth of the Ag layer. This improvement of the Ag crystallinity can be explained by the decrease in the kinetic energy of the Ar atoms backscattered on the Ag sputter target surface.