Superelastic alloy based electrical interconnects for highly stretchable electronics

Yangyong Zhao,Shuqi Wang,Ting Zhang,Lianhui Li,Simin Feng,Weifan Zhou,Xianqing Yang,Tie Li,Yixiang Shi,Yuanyuan Bai

doi:10.1038/s41528-022-00142-2

Abstract

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.

Highlights

Over the past decade, stretchable inorganic electronics based on structural design has developed rapidly[1,2,3,4,5,6,7]
According to the way of encapsulation, the electrical interconnects can be classified into two categories, including free-standing designs housed in microfluidic enclosures[3,7] and those embedded in the flexible substrate[6,8]
The results indicate that compared with conventional metals, the elastic stretchability of interconnects could be significantly improved by Ni-Ti alloys with a rate of up to 196%

Summary

Introduction

Stretchable inorganic electronics based on structural design has developed rapidly[1,2,3,4,5,6,7]. The comparison results confirm the speculation that by increasing the intrinsic elastic strain limit of the material through the utilization of superelastic alloys, elastic stretchability of the interconnect could be improved significantly.

Results

Conclusion