Simulation study on physical parameters ruling unipolar resistance switching of sputter-deposited silicon oxide film on Si substrate

Abstract

This paper performs Monte Carlo simulations to elucidate the physical parameters that rule the unipolar switching process in sputter-deposited Si oxide films, where the metal/sputter-deposited Si oxide film/Si substrate stack structure is assumed. Simulation parameters are based on the results of experiments performed in parallel. Generations of simple bond breaking, oxygen vacancies, metallic Si sites, and E″ centers are implemented in the simulation algorithm, where various chemical parameters are used to control bonding conditions. In this study, the impact of hole injection from the Si substrate on the switching operation is also discussed. All-positive voltage stress mode for both the electroforming process (or set process) and the reset process and all-negative voltage stress mode for both the electroforming process (or set process) and the reset process are compared in detail as to their effect on the film’s degradation process.The comparison of the two different stress modes reveals that the positive stress mode does not yield devices with stable, repeatable switching. On the other hand, the negative stress mode results in stable, repeatable switching. It is strongly suggested that the difference stems from the physical asymmetry of the electrode materials; that is, the energy spectra of electrons injected from the Si substrate has a wide range in the all-positive stress mode and the energy transfer efficiency from electrons injected from Si substrate to the atomic bonding sites is small due to the large tunnel probability, which does not result in the successful switching of the Si oxide film. The role of hole injection from the n-Si substrate on the negative-stress-mode switching process is also discussed. These new findings should contribute to the design methodology of such resistance switching devices.