The role of biasing electric field in intrinsic resistive switching characteristics of highly silicon-rich a-SiOx films

Abstract

The resistive switching behaviors are investigated in highly silicon-rich SiOx (x = 0.73) films, which are deposited using the plasma enhanced chemical vapor deposition method. For the Pt/SiO0.73/Pt structures, after the forming process the reset voltages (∼0.7 V) are lower than the set voltages (∼1.7 V). The metal-free structures N+-Si/SiO0.73/N++-Si/Pt show almost the same switching behaviors as those of Pt/SiO0.73/Pt structures, demonstrating an intrinsic resistive switching mechanism. We use the silicon dangling bonds (Si-DBs) percolation model to explain this. It is based on the biasing electric field decreasing the bond strength and leading to the breakage of Si–O bonds in SiOx films. Consequently the new Si-DBs are created and will contribute to form the dangling bonds percolation path. The temperature dependence of forming voltages is investigated. The forming voltages show no obvious changes and the forming process will occur as soon as the sweeping voltage reaches ∼10.5 V, even if the temperature decreases to 5.5 K. It indicates that the electric field plays an important role during the forming processes. Moreover, through the analysis of X-ray photoelectron spectroscopy and electron spin resonance signals, it can be concluded that the •Si≡Si3 and •Si≡Si2O DBs centers are the main components in Si-DBs percolation path of SiO0.73 films.