Mechanically stable, flexible, and stretchable metal–insulator–semiconductor-ferroelectric thin-film transistors for micro-LED display applications

We report flexible and stretchable, ferroelectric thin-film transistors (FE-TFTs) based on a metal–insulator–semiconductor-ferroelectric (MISF) structure. The devices are fabricated on polyimide (PI)/polydimethylsiloxane (PDMS) substrate. During the MISF fabrication process, we could obtain conventional oxide TFTs (SW-TFTs) by etching out the bottom ferroelectric (FE) layer. This leads to the advantage of fabricating both FE-TFT and conventional oxide TFT simultaneously. The fabricated FE-TFTs exhibited a memory window of 9.1 V and showed stable operation under bending on a cylinder of 1 mm radius. The FE-TFTs were first fabricated on the PI substrate and cut and transferred onto a PDMS substrate to achieve a stretchable device. The devices maintained stable operation under biaxial stretching up to 30% and demonstrated reliable performance for 100 hrs. For display application, we proposed a 3T0C circuit with FE-TFTs without a capacitor for pulse-width modulation (PWM) mode in micro-LED displays. The proposed FE-TFTs could be used for next-generation flexible and stretchable displays.