Direct evidence for stress-induced texture evolution and grain growth of silver thin films upon thermal treatment and self-ion bombardment

Abstract

Common failure mechanisms in microelectronics, such as electromigration, creep and fatigue, can be positively influenced by microstructure optimization. In this paper a combination of post-deposition heat treatment and self-ion bombardment is proposed as a valid candidate to gain control over the microstructure of (111) fiber textured thin silver films. Irradiation can induce a strong in-plane texture and hence lead to biaxially textured films through a process of selective grain growth. Moreover, we report microstructural stability of the irradiated regions over a wide range of temperatures (up to 600°C), in contrast to non-irradiated portions of the film, which underwent abnormal growth of the (100) out-of-plane oriented grains, and a consequent texture change, at temperatures as low as 195°C. The thermal stress induced in the film upon heat treatment was quantified in situ and its role in texture change elucidated.