Forming-free performance of a-SiN _x :H-based resistive switching memory obtained by oxygen plasma treatment

An a-SiN _x -based resistive random access memory (RRAM) device with a forming-free characteristic has significant potentials for the industrialization of the next-generation memories. We demonstrate that a forming-free a-SiN _x O _y RRAM device can be achieved by an oxygen plasma treatment of ultra-thin a-SiN _x :H films. Electron spin resonance spectroscopy reveals that Si dangling bonds with a high density (10¹⁹ cm^-3) are distributed in the initial state, which exist in the forms of Si₂N≡Si·, SiO₂≡Si·, O₃≡Si·, and N₃≡Si·. X-ray photoelectron spectroscopy and temperature-dependent current analyses reveal that the silicon dangling bonds induced by the oxygen plasma treatment and external electric field contribute to the low resistance state (LRS). For the high resistance state (HRS), the rupture of the silicon dangling bond pathway is attributed to the partial passivation of Si dangling bonds by H⁺ and O^2-. Both LRS and HRS transmissions obey the hopping conduction model. The proposed oxygen plasma treatment, introduced to generate a high density of Si dangling bonds in the SiN _x O _y :H films, provides a new approach to forming-free RRAM devices.