Texture and surface morphology evolution of Ag(Cu) layers on indium tin oxide thin films

Abstract

The evolution of surface morphology and (1 1 1) texture of Ag metallization on indium tin oxide (ITO) were improved by Cu additions to the Ag layer. X-ray diffraction (XRD) and atomic force microscopy (AFM) were used to characterize the surface morphology and the texture evolution of Ag(Cu). These results were compared with those obtained from pure Ag on ITO. After thermal annealing, AFM and XRD data show different modes of surface morphology evolution and crystallographic texture evolution with thermal annealing temperature. Differences in surface and texture between Ag(Cu) and Ag films were explained in terms of surface energy and grain boundary grooving as a function of annealing temperatures. The addition of Cu atoms into the silver thin films influenced the grain growth by modification of surface energy and/or adatom mobility. Rutherford backscattering spectrometry (RBS) and electrical resistivity measurements showed good thermal stability of Ag(Cu) in vacuum at temperatures varying from 300 to 600 °C for 1 h. AFM, RBS and electrical resistivity data also confirmed the absence of agglomeration occurrence during the annealing process. The enhanced texture and thermal stability indicated that Ag(Cu) alloy films constitute potential contact materials for MOSFET for better electromigration resistance and for optical devices such as flip-chip light-emitting diodes.