A quantitative strain analysis of a flexible single-crystalline silicon membrane

This study presents a quantitative strain analysis of a single-crystal Si membrane for high performance flexible devices. Advanced thinning and transfer methods were used to make flexible single-crystal Si devices. Two Si membrane strain gauges, each with a different stack, were fabricated on a polydimethylsiloxane/polyimide film using a silicon-on-insulator wafer. One gauge contains a 10-mu m-thick handling Si layer, whereas the handling Si layer was completely removed for the other case. Although the Si membrane with the 10-mu m-thick handling Si layer is flexible, the strain applied to the active Si layer (0.127%) is three times higher than the strain applied to the Si membrane without the handling Si layer (0.037%) at a bending radius of 5mm. This leads to the more reliable electrical and mechanical performance of the device fabricated on the Si membrane without the handling Si layer. The experimental results were verified through a finite element method simulation and analytical modeling. The quantitative strain analyses for flexible devices suggested here can expedite the realization of high performance flexible electronics using a single crystal silicon active layer. Published by AIP Publishing.