Light-Induced Thin-Film Transfer Processes Based on Phase Transition of GeSbTe and ITO Sacrificial Layers

In the upcoming ubiquitous era, wearable/flexible electronics are spotlighted to get various types of numerous information in real time. Several researchers have investigated flexible materials, and developed diverse thin-film transfer methods. However, there are some limitations of the intrinsic material unstabilities, and low production yield. Here, light-induced thin-film transfer methods are reported by using new transfer mechanism of phase transition in sacrificial materials. Lift-off conditions with high-energy laser are delicately optimized by theoretical calculations and experiments to minimize mechanical/thermal damages of the upper thin-film devices. The selected sacrificial materials of GeSbTe (GST) and indium tin oxide (ITO) with the 300 nm thickness are delaminated from a transparent and rigid glass substrate by irradiating the excimer laser to the surface of the sacrificial layer. The laser-based exfoliation mechanism of GST and ITO films are comprehended by various material surface analyses. Eventually, flexible oxide thin-film transistors (TFTs) are successfully demonstrated through light-induced exfoliation process, showing the usability of the developed transfer technique to future practical applications.