Nanomechanical Analysis of a UV Treated Ag Thin Film Based on a Three-Step Oxidation Model.

Nanoindentation was used as the main method to measure the change in nanomechanical properties on the surface of an Ag thin film due to UV treatment. The 4-point probe method, X-ray diffraction (XRD), and atomic force microscopy (AFM) were used to measure the electrical, crystallographic, and morphological properties, respectively. During a UV treatment time of between 1 and 3 minutes, the sheet resistance increased dramatically to 0.55 Ω/sq. (the sheet resistance was 0.16 Ω/sq. prior to UV treatment) and these results were supported by a proportional decreased in XRD intensity. Thereafter, the sheet resistance decreased and the XRD intensity increased in response to increases in UV treatment time. These results were related to a change in crystal structure from Ag to AgOx, which could also have caused the change in sheet resistance. Based on these results, we propose a 3-step oxidation model of an Ag thin film according to UV treatment time. This proposal has been proven by nanoindentation testing.