Electrical current distribution across a metal-insulator-metal structure during bistable switching

Combining scanning electron microscopy and electron-beam-induced current im aging with transport measurements, it is shown that the current flowing acr oss a two-terminal oxide-based capacitor-like structure is preferentially c onfined in areas localized at defects. As the thin-film device switches bet ween two different resistance states, the distribution and intensity of the current paths, appearing as bright spots, change. This implies that switch ing and memory effects are mainly determined by the conducting properties a long such paths. A model based on the storage and release of charge carrier s within the insulator seems adequate to explain the observed memory effect . (C) 2001 American Institute of Physics.