Nanolaminate with alternating layers of nanocrystalline Cu and amorphous CuZrTi is suggested as highly stretchable and conductive interconnect material in stretchable devices. 50 nm nanocrystalline Cu and 20 nm amorphous CuZrTi are the optimum thicknesses of the constituent layers, which result in an elastic deformation limit of 3.33% similar to that of the monolithic amorphous CuZrTi film and an electrical conductivity of 11.83 S/μm corresponding to 70% of that of the monolithic nanocrystalline Cu film. The enhanced elastic deformability and conductivity of the nanolaminates enable the maintenance of the interconnect performance for cyclic stretching with a tensile strain of 114% in the form of a free-standing serpentine structure and a tensile strain of 30% in the form of an ordinary circular coil on an elastomer substrate.
Keywords: electrical conductivity; mechanical property; nanolaminate; reliability; wearable devices.