Modulation of oxygen transport by incorporating Sb2Te3 layer in HfO2-based memristor

The oxygen transport plays an important role on the uniformity of the transition metal oxides (TMOS) memristors. Here, the effect of incorporating Sb2Te3 layer into TiN/HfO2/Pt memristor on oxygen transport has been systematically explored. The experimental results reveal that the memristor with Sb2Te3 incorporation at TiN/HfO2 interface has improved switching uniformity and memory window. Further theoretical calculations demonstrate that Sb2Te3 is a proper oxygen reservoir as oxygen possesses very low formation energy and migration barrier in Sb2Te3 with many vacancies. During the operation process, the Sb2Te3 will gain more oxygen from the HfO2 layer than TiN once the applied voltage reaches up to forming voltage, producing more oxygen vacancies ( VOs) in the HfO2 layer, compared with the device without the Sb2Te3 layer. Thus, the VOs conductive filaments (CF) in the HfO2 layer will be thick, resulting in a decrease in the randomness of CF's formation/rupture and, in turn, improving the device uniformity. Our findings provide an in-depth understanding of the oxygen reservoir in TMOS memristors, which is of great significance for the design and development of memristors.