Influence of residual stress and film thickness on crystallographic orientation in Al thin films deposited by bias sputtering

Abstract

Al thin films with various residual stress and him thickness were deposited by bias sputtering. Residual stress and relative intensity of the (200) to (111): plane of Al thin films were measured by x-ray diffraction. When film thickness is fixed at 1 mu m below the residual stress of similar to 80 MPa, AZ thin films have a (111) orientation, but above this stress, a (100) orientation. If Al thin films are in the high residual stress of similar to 145 MPa, crystallographic orientation changes to a (100) from a (111) orientation as film thickness increases to 2 mu m from 1 mu m. However, Al thin films with the residual stress of similar to 25 MPa have a (111) orientation regardless of film thickness. Total energy for Al thin films of a (100) and a (111) orientation was calculated as a function of residual stress and film thickness. These experimental results could be explained by the minimization of the sum of strain energy and surface energy in the films. (C) 1998 American Vacuum Society.[S0734-2101(98)04106-2].