Reactive sputter deposition of zinc oxide: Employing resputtering effects to tailor film properties

In sputter deposition, growth rate and total pressure are connected by the Keller-Simmons relation. Upon deposition of thin zinc oxide films in an argon-oxygen atmosphere, we have observed a deviation from the expected behavior. In this report, we provide evidence that energetic particles bombarding the growing film cause this deviation by resputtering. The influence of this ion bombardment on film growth is selective with respect to the orientation of crystalline grains, and hence an improved crystallographic texture is achieved. Based on these observations, we propose a simple procedure, which allows the identification of a process window where the films are deposited at a high rate, yet have a pronounced preferential orientation and a small roughness accompanied by low stresses.