The Role of CuAlO Interface Layer for Switching Behavior of Al/ $\hbox {Cu}_{x}\hbox {O}$ /Cu Memory Device

The interface layer between a reactive electrode and switching metal oxide is quite critical to improve the switching characteristics, but the intrinsic roles of this interfacial layer as oxygen reservoir or switching layer are still controversial. In this letter, we investigated the switching behavior of Cu_xO-based device by fully removing the top insulating Cu₂O layer, with lower conductive gradient Cu_xO layer left. The devices with Pt/gradient Cu_xO/Cu structure were shorted; however, other devices with Al/gradient Cu_xO/Cu structure still functioned normally. We suggest the interface layer formed between Al and Cu_xO acts as the switching layer. The results of an annealing experiment further reinforce this conclusion. The samples with preannealing before Al electrode deposition show similar characteristics with the nonannealed samples; however, the postannealing devices exhibit tremendous difference. Both R_ini and V_forming increase with the annealing temperature greatly.