Percolation theory based model of conduction mechanism and characteristic contradiction in ZnO RRAM

Resistive random access memory (RRAM) has been intensively investigated for nearly two decades. However, RRAM has not been applied widely in the market because of the poor characteristics, such as reliability and uniformity, which could be improved by the accurate comprehension of the mechanism. In this paper, a model based on percolation theory is proposed to simulate the I-V characteristics of ZnO resistive switching memory. It demonstrates that three different conductions of space charge limited current, Poole–Frenkel effect, and thermionic emission are determined by the relationship between the oxygen vacancy concentration and the bias. Furthermore, this model well explains the effect of conductive filaments' diameter and compliance current on the I-V characteristics of ZnO resistive switching memory, which demonstrates the rationality of the percolation model.