Materials and Patterning Techniques for Macroelectronics Yugang Sun, Shawn Mack, Matthew Meitl and John A. Rogers Department of Materials Science and Engineering and Frederic Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA *Tel: (217) 244-4979, Fax: (217) 333-2736, E-mail:
[email protected] Abstract Flexible thin film transistors (TFTs) with high performance can be fabricated by using printable arrays of microstructured Si ribbons or GaAs wires (µs-Si or µs-GaAs) generated from high-quality, single-crystal, bulk wafers. The resulting Sibased MOSFETs and GaAs-based MESFETs on thin plastic substrates exhibit excellent electrical and mechanical (i.e. bending) properties. The combined use of these materials and printing techniques may advance the development of practical technologies for emerging applications of lightweight, flexible ‘macroelectronic’ systems in consumer, space, and military applications. Introduction Large-area flexible macroelectronic circuits can be used in low-end applications, such as paperlike displays, as well as high-end applications such as foldable and expandable antennas for military and space communication. Previous studies indicate that thin substrates made of electrically inert polymers can be used with semiconductors based on small molecule organics, polymers or amorphous silicon to build active matrix backplanes for flexible displays and related systems. The performance that can be obtained from these classes of semiconductor materials is, however, relatively modest (comparable to c:Si), and they have uncertain reliability. An alternative approach to flexible electronics involves direct printing of high-quality semiconductors (with single crystallinity) onto plastic followed by depositing and patterning other materials at relatively low temperatures (
