Field and polarity dependence of time-to-resistance increase in Fe-O films studied by constant voltage stress method

Constant voltage stress (CVS) was applied to Fe-O films prepared by a sputtering process to investigate a stress-induced resistance increase leading to a fundamental mechanism for switching behaviors. Under the CVS, an abrupt resistance increase was found for both stress polarities. A conduction mechanism after the resistance increase exhibited non-Ohmic transport. The time-to-resistance increase (t(r)) under the CVS was revealed to strongly depend on stress voltage as well as the polarity. From a polarity-dependent resistance increase determined by a time-zero measurement, the voltage and polarity-dependent t(r) were discussed on the basis of field- and structure-enhanced thermochemical reaction mechanisms.