Controlled formation of straight-sided buckles in patterned Ta films on glass substrates

We report on the controlled formation of buckle driven delaminations in patterned Ta films composed of parallel strips with different widths. It is found that the strip width can precisely control the morphologies of the buckling patterns due to the edge effect. For narrower strips, complete straight-sided buckles perpendicular to the strip edges are always observed. For wider strips, straight-sided buckles form at the edges while irregular buckle networks form in the central regions. For the strips with a critical width, various buckling phenomena, including complete and half straight buckles, wavy buckles, bifurcation and coalescence behaviors, can coexist in the same strip. The structures and morphologies of the straight-sided buckles appeared in the strips with different widths have been characterized and analyzed in detail.