Mechanism for resistive switching in chalcogenide-based electrochemical metallization memory cells

Abstract

It has been reported that in chalcogenide-based electrochemical metallization (ECM) memory cells (e.g., As2S3:Ag, GeS:Cu, and Ag2S), the metal filament grows from the cathode (e.g., Pt and W) towards the anode (e.g., Cu and Ag), whereas filament growth along the opposite direction has been observed in oxide-based ECM cells (e.g., ZnO, ZrO2, and SiO2). The growth direction difference has been ascribed to a high ion diffusion coefficient in chalcogenides in comparison with oxides. In this paper, upon analysis of OFF state I–V characteristics of ZnS-based ECM cells, we find that the metal filament grows from the anode towards the cathode and the filament rupture and rejuvenation occur at the cathodic interface, similar to the case of oxide-based ECM cells. It is inferred that in ECM cells based on the chalcogenides such as As2S3:Ag, GeS:Cu, and Ag2S, the filament growth from the cathode towards the anode is due to the existence of an abundance of ready-made mobile metal ions in the chalcogenides rather than to the high ion diffusion coefficient.

Microstructural transitions in resistive random access memory composed of molybdenum oxide with copper during switching cycles

“…A similar discussion was conducted based on the shape of the I-V curve in a previous report. 66 There are two reset modes. When the CF does not bind the TE and the BE, the CF becomes thin overall and tends to shrink towards the BE.…”

A nonlinear HP-type complementary resistive switch

“…This corresponds to the physical case of a filament with a large base getting thinner near the end, presumably also the relevant physical case. 16,29 As we see in Fig. 2(b) for several nonlinearities, while all describe slightly different memristors, the φ − q relation remains bijective, as also implied by Eq.…”

“…We cannot expect the bridge to be a rectangle however, rather it might be some ill-defined wegde-like or pyramidal structure, 1,3,10,16,28 see Fig. 1(b) or consist of several fused channels.…”

“…5,6 Various other interesting applications in dynamical systems have recently been discussed as well, such as memristor based oscillators. 7 A single RS-cell consists of a transition metal oxide (TMO) like titanium dioxide [8][9][10][11] or manganites 12,13 sandwiched in between two electrodes, or electrochemical metallization cells, 1,[14][15][16] for which one of the electrodes must be electrochemically active. Connected to an external current or voltage, the elements' resistance toggles between a high and low resistive state, R off and R on , depending on the amount of charge or applied voltage flux.…”

Coexistence of two types of metal filaments in oxide memristors

“…The whole resistance is always dominated by the reverse-biased SB. 25,28 For Cu/ZnO/Pt, the resistance is determined by the ZnO/Pt SB at a positive bias; while at a negative bias, the resistance is determined by the Cu/ZnO SB. It follows that in the positive (negative) FORM process, the voltage drop is mostly across the ZnO/Pt (Cu/ZnO) Schottky junction.…”