Nonvolatile Crossbar Switch Using $\hbox {TiO}_{x}/ \hbox {TaSiO}_{y}$ Solid Electrolyte

A nonvolatile crossbar switch using a dual-layered TiO_x/TaSiO_y solid electrolyte, "NanoBridge," has been developed. NanoBridge is scalable to 50 nm and programmed at low voltage while keeping a low ON-resistance. The high compatibility with a back-end-of-line processing for CMOS integrated circuits is achieved by using the dual-layered TiO_x/TaSiO_y solid electrolyte, in which a barrier (Ti) is inserted on Cu and changes to an oxide during the subsequent process step. TiO_x has the double role of preventing Cu oxidation during TaSiO_y deposition and acting as a solid electrolyte itself. A resistive-change characteristic is investigated in terms of the inserted barrier dependence. At an optimal barrier insertion, the integrated switch shows bipolar switching characteristics with a high OFF-/ON-resistance ratio of 10⁶. The developed device is applied to a 4 × 4 crossbar switch integrated with the CMOS circuit. The crossbar switch is configured without select transistors and transfers signals properly.