Nano-ionic solid state resistive memories (Re-RAM): A review

ArticleinJournal of Nanoscience and Nanotechnology 17(1):72-86 · January 2017with 102 Reads
DOI: 10.1166/jnn.2017.12805
Abstract
Nano-ionic devices based on modest to fast ion conductors as active materials intrigued a revolution in the field of nano solid state resistive memories (the so-called Re-RAM) ever since HP labs unveiled the first solid state memristor device based on titanium dioxide (TiO2). This has brought impetus to the practical implementation of fourth missing element called "Memristor" correlating charge (q) and flux (φ) based on the conceptual thought by Chua in 1971 completing a missing gap between the passive electronic components (R, C and L). It depicts various functional features as memory element in terms of ionic charge transport in solid state by virtue of external electric flux variations. Consequently, a new avenue has been found by manipulating the ionic charge carriers creating a fast switching resistive random access memory (Re-RAM) or the so-called Memristors. The recent research has led to low power, faster switching speed, high endurance and high retention time devices that can be scaled down the order of few nanometers dimension and the 3D stacking is employed that significantly reduces the die area. This review is organized to provide the progress hitherto accomplished in the materials arena to make memristor devices with respect to current research attempts, different stack structures of ReRAM cells using various materials as well as the application of memristive system. Different synthesis approaches to make nano-ionic conducting metal oxides, the fabrication methods for ReRAM cells and its memory performance are reviewed comprehensively.

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  • ... A variety of alternatives to traditional information processing devices have been proposed, boosting new scientific research in semi- conductor principles and technologies [1]. In this frame, memristors-or resistive switching materials, as the two terms identify the same switching behavior [2,3]-were identified as valuable candidates for alternative nanoelectronic devices [4][5][6][7], with particular reference to nonvolatile memories and neuromorphic applications. ...
  • ... The switching me- chanism in memristor is attributed to the variation in ionic, electronic and thermal properties [15]. Although, there are ample reports on switching mechanism of memristor, but till date none of the mechan- isms are elucidated, rather they are suggested on the basis of theoretical understanding and/or with the aid of advanced physical and electrical characterization techniques [15,16]. The physics involved underneath the resistive switching operation in titanium dioxide based memristor is perceived as being one of the following: (i) the formation and rupturing of conducting filaments (kind of dendrites) originated from BE [17][18][19][20][21][22], and (ii) electrical trap related process [22][23][24]. ...
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