Bendability of single-crystal Si MOSFETs investigated on flexible substrate

This letter reports on a device layer transfer (based on thermal bonding and grinding backside Si) process and device characteristics of Si MOSFETs on a flexible substrate, focusing mainly on the mechanical bendability of the device and resistance to fatigue. The results demonstrated a well-optimized bonding process, as indicated by the nearly indiscernible performance difference (e.g., subthreshold slope, V/sub th/, and I/sub dsat/) before and after the bonding of Si with the flexible substrate. The device characteristics indicate excellent bendability of Si MOSFETs on flexible substrate (e.g., for radius tested down to /spl plusmn/72 mm) and good immunity to fatigue (e.g., negligible performance drift tested up to /spl sim/10/sup 3/ bending cycles with a radius of /spl plusmn/126 mm). Results suggest the feasibility of this approach in achieving high-performance MOSFETs for applications in performance-sensitive and flexible electronics.