Enhancement of EPIR Switching Characteristics of PCMO RRAM Using Oxygen Deficient Al2Ox Diffusion Barrier
Mithun Kumar, Ramasahayam
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Resistive random access memory has gained lots of interest in the last decade as a promising replacement for non-volatile memory. Device retention stability and electric pulse induced resistance switching (EPIR) ratio (percent of change in resistance between the low and high resistance states) are very important characteristics of any resistive memory devices. Pr0.7Ca0.3MnO3 (PCMO) is one of the most promising materials which exhibit EPIR switching, however it suffers some short comings as low retention stability and low EPIR ratio. This work investigated the effect of oxygen ion/vacancy buffer layer of Al2Ox in metal/buffer layer/PCMO/Metal heterostructure prepared by RF sputtering in Ar only and Ar:O2 atmosphere. The diffusion barrier of the same is integrated into Pr0.7Ca0.3MnO3 (PCMO) to study the resistance switching and retention properties of this heterostructure. The internal Al2Ox barrier is placed between the “bulk” PCMO region of the sample and a top PCMO active interface region. The Al2Ox layer is believed to reduce/prevent change in the ion/vacancy concentration in the interface region after a certain concentration is set by the application of a short electric pulse, and also enhances the EPIR switching ratio. The switching performance of the buffer layer heterostructure has indicated that the buffer layer combined with top 10nm is active region in resistance switching. This work also addressed a model for the enhancement of the switching.