Sputtering and Evaporating of High Density (111)-textured Ag Nanotwinned Films on Sapphire Wafers

The excellent properties of nanotwinned structures have been a hot area of research in recent years.Silver (Ag) has the lowest stacking fault energy (SFE) among all FCC metals, which has a strong tendency to form a twin structure.Also, sapphire substrates are ideal for use in LED applications due to high-temperature resistance, high strength, good electrical insulations, and low dielectric loss.Depositing Ag nanotwinned films on sapphire substrates can serve as a perfect candidate for die bonding in LED manufacturing.In this study, two deposition methods had been demonstrated for the fabrication of high density (111)-textured Ag nanotwinned films on sapphire wafers.Microstructural analyses show that both the sputtered and evaporated Ag grains presented a high density of twin structure.The cross-sectional EBSD analysis of the sputtered Ag nanotwinned film indicated a highly (111)-preferred orientation to 34.6% of the overall grains.Further, the sputtering process allows the production of surface roughness of the Ag nanotwinned film up to 65.1 nm.The epitaxial growth of Ag nanotwinned films with (111)-preferred orientation can be utilized by both the deposition methods.