Fabrication of large-scale flexible silicon membrane by crystal-ion-slicing technique using BCB bonding layer

Flexible electronics is one of the most emerging fields of future electronic devices. The application of flexible inorganic membrane provides a feasible way to realize high-performance electronic device with desired deformation ability. In this paper, a method to fabricate large-scale flexible monocrystalline silicon membrane by crystal-ion-slicing (CIS) technique using benzocyclobutene (BCB) bonding layer is reported. With introduction of BCB bonding layer, a 1-μm-thick Si membrane with the size of 8 × 8 mm can be obtained on the polyimide substrate using the conventional CIS technique. Morphology and structure characterizations confirm the high crystallinity and structural integrity of the as-fabricated silicon membrane. Typical piezoresistive effect can be observed in the measured dependence of the resistance of Si membrane on the bending strain, indicating the potential to using this method to construct flexible force sensor with high stability and sensitivity.