The improved resistive switching properties of TaOx-based RRAM devices by using WNx as bottom electrode

The WNx films were successfully prepared on silicon-based substrates as bottom electrodes for the resistive random access memory (RRAM) cells in Pt (top)/TaOx/WNx (bottom) sandwich structure. The reproducible resistive switching (RS) characteristics of these cells were studied systematically for RRAM applications. The advantages of adopting WNx instead of Pt as bottom electrode material were demonstrated, such as the improvement of the low resistive state value, the RS endurance and the uniformity of RS parameters. The X-ray photoelectron spectroscopy revealed that both the oxygen vacancies in the TaOx film and the interfacial tungsten oxynitride (WON) layer formed between the dielectric TaOx film and the WNx bottom electrode play key roles in the RS performance improvement.