Role of Oxygen Vacancies at the TiO2/HfO2 Interface in Flexible Oxide-Based Resistive Switching Memory

Flexible memory is highly desirable for data storage in portable wearable electronics. Here, a flexible bilayer TiO2/HfO2-architecture-based resistive random access memory (RRAM) is fabricated a on polyethylene naphthalate (PEN) substrate, and exhibits outstanding uniformity, high durability, and excellent mechanical flexibility. The coefficients of variations for high and low resistance state are approximate to 3.2% and approximate to 3%, respectively. No performance degradation is observed under mechanical stress with bending radius ranging from 70 to 10 mm. Interestingly, the performance degradation after long-term stability tests can be recovered. An asymmetric hourglass-shaped oxygen vacancy (Vo) distribution at the HfO2/TiO2 interface plays a key role in high performance of this flexible RRAM device. The proposed flexible RRAM devices have potential applications in wearable electronics.