Superelastic alloy based electrical interconnects for highly stretchable electronics

To achieve stretchable inorganic electronics, improving elastic stretchability of the electrical interconnects becomes a bottleneck needed to be addressed. Here, we propose a material of Ni-Ti superelastic alloy for the design and fabrication of deformable interconnects, whose intrinsic elastic property overcomes the low intrinsic elastic strain limit of conventional metals. The serpentine interconnect made by Ni-Ti alloy with an intrinsic elastic strain limit of ~7.5% represents a much higher elastic stretchability than conventional Cu interconnect. The deformation behavior of the interconnect is systematically investigated through finite element analysis (FEA) simulations and experiments. The results reveal that the interconnect exhibits an elastic stretchability up to 196%, and its resistance only changes by 0.4% with 100% strain. Moreover, the potentials and challenges of other superelastic alloys as electrical interconnects are discussed. The proposed superelastic alloys fundamentally boost the stretchable properties of electrical interconnects, which would open up opportunities for flexible and stretchable electronics.