Mass fabrication of resistive random access crossbar arrays by step and flash imprint lithography

Step and flash imprint lithography (SFIL) is a promising method recently used for next generation lithographic technology because it is a high-speed process that can be carried out at room temperature and low pressures. Improvements made to SFIL enable the replication of crossbar patterns with a high resolution and the development of suitable materials and techniques to achieve high resolution capability. In this study, SFIL is used to fabricate high-density random access crossbar arrays based on a NiO resistive switching system. The bottom and top electrodes are transferred onto silicon wafers perpendicular to each electrode using the inductively coupled plasma reactive ion etching (ICP-RIE) technique. Direct metal etching without a wet-based process minimizes damage to the electrode surface. The I–V curves of individual active cells (70 × 70 nm²) for crossbar arrays reveal the unipolar resistive switching (RS) behaviour of the fabricated device. A high off/on resistance ratio (>10⁴) and reproducible resistance switching characteristics for each active cell were found in different fields and for different wafers. The experimental data indicate that high-density crossbar arrays can be well replicated and that the electrical performance of these arrays is reliable.