a thin film x y al n alloy preferably deposited with an intrinsic tensile stress significantly enhances the piezoelectric properties of aln . the alloy contains y percent of the compound xn , where x is selected from the group consisting of yb , ho , dy , lu , tm , tb , and gd . the percentage of xn preferably lies in the range 10 - 60 %, and the stress is preferably in the range 200 mpa - 1 . 5 gpa . the film is useful in mems devices .