In-plane deformation mechanics of highly stretchable Archimedean interconnects

Stretchable inorganic electronics are very attractive for many applications, which require large deformation during stretching. Archimedean–inspired interconnect designs can offer and achieve high level of stretchability under extreme deformations. Here, we systematically investigate the relationship between stretchability and the geometrical parameters under in-plane deformation. The stretchable structures are made of amorphous silicon (a-Si), which cracked at very small strain 1.6%. Finite element method (FEM) was carried out to simulate the maximum strain/stress of interconnects. The results show that high stress appears at the base and the half-circle of the Archimedean interconnects. Experimental results agree well with the numerical modeling, both showing that the stretchability more than double when the straight line at the base is replaced by two lines in series. Our results demonstrate a stretchability up to 1020% and 605%, respectively for two types of Archimedean interconnect. The results indicate that the narrower width, the larger gap separated the straight lines (higher radius), and the longer straight lines will achieve lower stress and high stretchability. Further, a numerical study is conducted to explore the mechanical performance of Poly-crystalline silicon based structures where the maximum bending strain should be up to 1%.