Fabrication of Single Crystal Silicon Micro-/Nanostructures and transferring them to Flexible Substrates

Micro/nanostructures of single-crystal Si, in the form of wires and ribbons, are promising building blocks for realizing high performance nano- to macro scale field-effect transistors (FETs). This work presents the method to fabricate single-crystal Si wires and ribbons from silicon-on-insulator (SOI) wafers using “top-down” fabrication strategy and transfer the same to ultra flexible substrates. Si wires with lengths ranging from 30 to 5000 μm and widths ranging from 4 to 50 μm have been fabricated. The parallel aligned wires are then successfully transferred, first to a flexible transfer substrates (PDMS) and then to the final receiver substrate (polyimide). Finally, the bending of Si wires has been investigated by bending them up to 220 degrees without breaking. Such a high bending of wires demonstrate the possibility of obtaining ultra flexible integrated electronics on flexible substrates.