Super-elastic Gold Conductors on Elastomeric Substrates
- PDF / 637,581 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 51 Downloads / 195 Views
H10.3.1
Super-elastic Gold Conductors on Elastomeric Substrates Catriona Chambers1, Stéphanie P. Lacour1, Sigurd Wagner1, Zhigang Suo2, Zhenyu Huang2 Department of Electrical Engineering and POEM, 2 Department of Mechanical and Aerospace Engineering Princeton University, Princeton, NJ 08544 1
ABSTRACT 3-D displays, sensor skins, mechatronic structures, and e-textiles will rely on deformable and stretchable electronic circuits. It is likely that such circuits will be made of rigid semiconductor islands interconnected with one-time deformable or even elastic metallization. However, free-standing metal films fracture at tensile strains in the order of one percent, well short of the approximately ten-percent extension needed for deformable circuits. We have discovered that flat metal lines made on an elastomeric substrate can be stretched reversibly by ten percent without losing electrical conduction. While this phenomenon of “super-elastic” conductive films is as of yet unexplained, it appears to originate in the diversion of mechanical strain around cracks in the film and through the elastomer substrate. We fabricated 1mm thick poly-dimethylsiloxane (PDMS) membranes with up to 50-nm thick, 1-mm wide gold lines deposited by electron beam evaporation. Then we evaluated the structure of the gold films by optical and scanning electron microscopy, and measured the electro-mechanical characteristics in a strain tester, with contact electrodes applied to the film. We find that 50 nm thick lines retain their electrical conduction up to 30 percent strain. Also, when the tensile strain is cycled between 0 and 10 percent, the electrical resistance in the stressed and relaxed states are reproducible. We will describe substrate and conductor preparation, and their structural and electro-mechanical properties. INTRODUCTION A developing area of macroelectronics is integrating circuits on flexible and deformable substrates. Potential applications for such devices include e-textiles, deformable sensitive skin and spherical sensors. Depending on the circuit’s eventual application, these circuits may be deformed only once or many times. One concept to making such circuits is to have the electronic components fabricated onto individual rigid “islands” on a flexible substrate. The islands help to protect the components from strain-induced deformation [1]. This concept however will rely on flexible metal interconnects to integrate the sub-circuits and components. Typical conductive interconnects prepared with Integrated Circuit (IC) technology are thin metallic films and present low critical strain and thus are not compliant and stretchable. This paper reports on a method whereby thin film metal is deposited onto an elastomeric substrate [2, 3, 4] and can withstand comparatively high strains up to 30%. The elastomeric substrate helps to disperse the strain locally around the interconnect allowing elongation beyond that of a theoretical free standing metal. First we describe the stretchable interconnect fabrication process and then presen
Data Loading...
