A Novel Nitrogen-doped SiO_x Resistive Switching Memory with Low Switching Voltages

摘要

Recently, nonvolatile memories based on resistive switching materials have attracted great attention due to their simple fabrication process, low power operation, fast speed and good scalability[l]-[3]. Many resistive switching memories based on transition metal oxide (TMO), such as NiO, TiO_2, CuO_x, WO_x, Ta_2O_5; etc., have been reported[2]-[7]. In our previous work, we used SiO as the active layer of RRAM for embedded memory applications, however, the switching voltage was a little bit high (about 5.5V) [8]. To improve the operating voltage, in this work, we doped nitrogen into the SiO_x active layer (i.e., Si_xO_yN_z) to introduce more traps and weaken the chemical bonds of the active layer SiO_x. It is believed that, with nitrogen doping, more vacancies will generate in the oxide layer, and thus the switching voltages can be effectively reduced. In this paper, a novel Cu/Si_xO_yN_z/W device was fabricated with the back-end process of CMOS technology, which is promising for 3D integration and embedded memory applications. This device exhibited unipolar behaviors with low switching voltages and high off/on resistance ratio. Based on the experiment results, switching mechanism of the device was discussed.