Bipolar resistive switching with unidirectional selector function in nitride/oxide heterostructures

In this work, we propose a self-rectifying Ni/SiNx/HfO2/p++Si resistive memory device to alleviate the sneak-path current occurring in crossbar array. The bilayer (Ni/SiNx/HfO2/p++Si) device exhibits a much higher rectification ratio (>104) in the low-resistance state for DC sweep mode and pulse mode than single-layer devices (Ni/SiNx/p++Si and Ni/HfO2/p++Si). The suppressed current of the bilayer device can be explained by the high Schottky barrier of the HfO2 layer under a negative bias. The modified read bias scheme in the crossbar array structure ensures a large number of word line (∼3971 at a read margin of 10%) using the advantage of the high rectification of the bilayer device. The bilayer device with the proposed read bias scheme is promising for high-density memory applications.