RESUMEN
We observe a gamma-irradiation induced change in electrically detected magnetic resonance (EDMR) in TiN/Ti/HfO2/TiN resistive random access memory (RRAM). EDMR measurements exclusively detect electrically active defects which are directly involved in the transport mechanisms within these devices. The EDMR response has an isotropic g-value of 2.001 ± 0.0003. The response increases dramatically with increased gamma-irradiation. We tentatively associate this EDMR response with spin dependent trap assisted tunneling (SDTAT) events at O 2 - centers coupled to hafnium ions. Although our study cannot fully identify the role of these defects in electronic transport, the study does unambiguously identify changes in transport defects caused by the ionizing radiation on defects involved in electronic transport in RRAM devices. This work also contributes more broadly to the RRAM field by providing direct, though incomplete, information about atomic scale defects involved in electronic transport in leading RRAM systems.
RESUMEN
The inevitable current overshoot which follows forming in filamentary RRAM devices is often perceived as a source of variability that should be minimized. This sentiment has led to efforts to curtail the overshoot by decreasing the parasitic capacitance using highly integrated 1T-1R or 1R-1R device structures. While this is readily achievable in single device test structures, it poses an intricate design constraint for memory array designs. Several papers (Degraeve et al., 2010, 2014; Fantini et al., 2013; Raghavan et al., 2013; Padovani et al., 2015) suggest that there is insufficient current to form stable filaments for small parasitic capacitances and/or low current compliance levels. Thus, the relationship between minimizing overshoot current and improved filament stability is tenuous. In this study, we utilize the forming energy-based understanding of filamentary forming to reveal that the parasitic capacitance should be optimized, rather than minimized for better filament control.