Review of Emerging New Solid-State Non-Volatile Memories

Abstract

The integration limit of flash memories is approaching, and many new types of memory to replace conventional flash memories have been proposed. Unlike flash memories, new nonvolatile memories do not require storage of electric charges. The possibility of phase-change randomaccess memories (PCRAMs) or resistive-change RAMs (ReRAMs) replacing ultrahigh-density NAND flash memories has been investigated; however, many issues remain to be overcome, making the replacement difficult. Nonetheless, ferroelectric RAMs (FeRAMs) and magnetoresistive RAMs (MRAMs) are gradually penetrating into fields where the shortcomings of flash memories, such as high operating voltage, slow rewriting speed, and limited number of rewrites, make their use inconvenient. For instance, FeRAMs are widely used in ICs that require low power consumption such as smart cards and wireless tags. MRAMs are used in many kinds of controllers in industrial equipment that require high speed and unlimited rewrite operations. For successful application of new non-volatile semiconductor memories, such memories must be practically utilized in new fields in which flash memories are not applicable, and their technologies must be further developed.

Polarization imaging in ferroelectric polymer thin film capacitors by pyroelectric scanning microscopy

“…The results agree well with a thermal model implemented numerically using finite element analysis. Ferroelectric materials have been the subject of increasing interest in recent decades, largely because of the development of methods for thin film and nanostructure fabrication, and subsequent integration into a wide range of electronic technologies, such as thermometry and thermal imaging, 1,2 electromechanical transducers, 3 nonvolatile memories, 4 organic electronics, 5 and energy storage, 6 as well as promising applications to organic photovoltaics, 7 solid-state energy harvesting, and refrigeration. 8,9 To further improve the performance and utility of ferroelectric materials, it is essential to be able to measure the spatial distribution of the polarization at high resolution.…”

Oxide Electronics and Vanadium Dioxide Perspective: A Review

“…Therefore, the phenomena of metalinsulator transition and switching have various potential applications in electronics and related fields of engineering [10], [46], [47]. Particularly, the TMO-based MOM structures demonstrating memory switching have been proposed as potential candidates for both nonvolatile and dynamic random-access memories [21]- [30]. Also, memory effects due to the electric field induced Mott transition (in cerium oxide particularly) have been studied in [140].…”

“…Note, however, that the memory effect, although manifested mainly by TMOs [21]- [29], is obviously not directly associated with the electron correlation phenomena.…”

Understanding the Resistive Switching Phenomena of Stacked Al/Al2O3/Al Thin Films from the Dynamics of Conductive Filaments

“…Some of these advantages are a simple memory structure (usually composed of MIM stacks), deep scalability, ultralow power consumption, fast write/erase speed, and long retention times [3]. Also, even though the precise physics behind the operation mechanism is still not fully understood, by using resistive switching and/or ion migration phenomena, there have been some advances in which, for many cases, single and/or multiple filamentary conduction paths can be formed or dissolved in the oxide, thus connecting or disconnecting both metal electrodes and, therefore, giving origin to both LRS and HRS [4,5]. This is important because a better understanding of the resistive switching phenomena could enable enhanced nonlinear applications like the ones previously described, while also providing better modeling tools for nonlinear devices and systems.…”

“…In unipolar mode, the resistive switching transitions (HRS ↔ LRS) of the oxide layer are obtained using the same polarity but different magnitudes of applied bias (while limiting the gate current at two current compliance levels). In bipolar mode, these transitions are obtained using different polarities of applied bias so that typical hysteresis loops in the -characteristics (Lissajous curves) are observed [3,5]. In any case, these resistive switching transitions require specific voltages so that SET and RESET would promote HRS → LRS (ON) and HRS ← LRS (OFF) transitions, respectively (see Figures 1(a)-1(b)).…”