Texture in evaporated Ag thin films and its evolution during encapsulation process

Abstract

The texture components of Ag films in evaporated Ag/Ti bilayers have been quantitatively characterized by X-ray pole figure analysis. The effect of an encapsulation process at elevated temperatures on the texture evolution has been explored as well. Both 〈111〉 and 〈511〉 fiber texture components were observed in the Ag films. The maximum 〈111〉 intensity is along the fiber axis that is parallel to the film normal and the maximum 〈511〉 intensity deviates slightly from the fiber axis by 1–2°. The latter component is attributed to the twinning of 〈111〉 oriented grains. The volume fraction and maximum intensity of the 〈111〉 texture are further enhanced by the encapsulation process as opposed to the reduced volume fractions of 〈511〉 and randomly oriented grains. Compared to the Al and Cu films processed under comparable conditions, the Ag films possess a stronger 〈111〉 texture intensity, a sharper distribution of 〈111〉 texture about the fiber axis, and a lower volume fraction of randomly oriented grains. Therefore, an improved electromigration resistance is expected in Ag films. Low resistivity values (1.7–2.2 μΩ cm) were obtained in the encapsulated Ag films as well as the as-deposited Ag films.