Microscopy study of the conductive filament in HfO2 resistive switching memory devices

Privitera, S.; Bersuker, G.; Butcher, B.; Kalantarian, A.; Lombardo, S.; Bongiorno, Corrado; Geer, Robert; Gilmer, D. C.; Kirsch, P. D.

doi:10.1016/j.mee.2013.03.145

Cited by 85 publications

(85 citation statements)

References 6 publications

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“…Among the many contenders for the next-generation of memory device, resistive switching memory based on metal oxides has emerged as the leading candidate [1]. Many metal oxides have been reported to show resistive switching properties such as TiO2 [2], HfO2 [3,4], Ta2O5 [5] etc. For resistive memory in general, highvoltage forming process is needed to initiate the switching, which will normally lead to high power consumption and increased circuit and operational complexity [1].…”

Section: Introductionmentioning

confidence: 99%

Forming-free resistive switching of tunable ZnO films grown by atomic layer deposition

Huang

Kiang

Morgan

et al. 2016

Microelectronic Engineering

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Undoped ZnO thin films with tunable electrical properties have been achieved by adjusting the O2 plasma time in the plasma enhanced atomic layer deposition process. The structural, compositional and electrical properties of the deposited ZnO films were investigated by various characterization techniques. By tuning the plasma exposure from 2 to 8 s, both resistivities and carrier concentrations of the resultant ZnO films can be modulated by up to 3 orders of magnitude. Forming-free TiN/ZnO/TiN resistive memory devices have been achieved by choosing the ZnO film with the plasma exposure time of 6 s. This deposition method offers a great potential for producing other un-doped metal oxides with tunable properties as well as complex multilayer structures in a single deposition.

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Section: Introductionmentioning

confidence: 99%

Forming-free resistive switching of tunable ZnO films grown by atomic layer deposition

Huang

Kiang

Morgan

et al. 2016

Microelectronic Engineering

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“…Recent conductive atomic force microscopy results have provided tomographic images of conductive filaments in ex situ electroformed SiO x [10]. In previous transmission electron microscopy (TEM) studies of RRAM devices that had been switched ex situ [11,12], the switched areas needed to be localized prior to the preparation of TEM specimens and great care was needed to avoid artifacts introduced by TEM specimen preparation. Most importantly, only the final states of the switching processes could be observed, making it impossible to follow the growth of conductive filaments or to deduce the nature of the switching mechanisms.…”

Section: Introductionmentioning

confidence: 99%

In situ transmission electron microscopy of resistive switching in thin silicon oxide layers

Duchamp¹,

Migunov²,

Tavabi³

et al. 2016

Resolution and Discovery

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Silicon oxide-based resistive switching devices show great potential for applications in nonvolatile random access memories. We expose a device to voltages above hard breakdown and show that hard oxide breakdown results in mixing of the SiO x layer and the TiN lower contact layers. We switch a similar device at sub-breakdown fields in situ in the transmission electron microscope (TEM) using a movable probe and study the diffusion mechanism that leads to resistance switching. By recording bright-field (BF) TEM movies while switching the device, we observe the creation of a filament that is correlated with a change in conductivity of the SiO x layer. We also examine a device prepared on a microfabricated chip and show that variations in electrostatic potential in the SiO x layer can be recorded using off-axis electron holography as the sample is switched in situ in the TEM. Taken together, the visualization of compositional changes in ex situ stressed samples and the simultaneous observation of BF TEM contrast variations, a conductivity increase, and a potential drop across the dielectric layer in in situ switched devices allow us to conclude that nucleation of the electroforming-switching process starts at the interface between the SiO x layer and the lower contact.

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“…In cases where it is not dielectric properties but rather spatially dependent conductivity, analysis of oxidation states and lateral distribution of anions, e.g. in bulk mixed ion conductors, can yield important information as they determine the number of available charge carriers or trap states (Privitera et al, 2013(Privitera et al, , 2015. Here, the resistance state of the memristor is defined by the oxygen or trap concentration profile; the ion conductivity is linearly dependent on mobility and concentration, the latter of which can be determined by EELS analysis of the metals oxidation state or even simpler but possibly less accurate by quantification of metal and oxygen contents from EDX data.…”

Section: Anion Movement Based Devicesmentioning

confidence: 99%

Transmission Electron Microscopy on Memristive Devices: An Overview

Strobel

Neelisetty

Chakravadhanula

et al. 2016

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This communication is to elucidate the state-of-the-art of techniques necessary to gather information on a new class of nanoelectronic devices known as memristors and related resistive switching devices, respectively. Unlike classical microelectronic devices such as transistors, the chemical and structural variations occurring upon switching of memristive devices require cutting-edge electron microscopy techniques. Depending on the switching mechanism, some memristors call for the acquisition of atomically resolved structural data, while others rely on atomistic chemical phenomena requiring the application of advanced X-ray and electron spectroscopy to correlate the real structure with properties. Additionally, understanding resistive switching phenomena also necessitates the application not only of pre-and post-operation analysis, but also during the process of switching. This highly challenging in situ characterization also requires the aforementioned techniques while simultaneously applying an electrical bias. Through this review we aim to give an overview of the possibilities and challenges as well as an outlook onto future developments in the field of nanoscopic characterization of memristive devices.

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Microscopy study of the conductive filament in HfO2 resistive switching memory devices

Cited by 85 publications

References 6 publications

Forming-free resistive switching of tunable ZnO films grown by atomic layer deposition

Forming-free resistive switching of tunable ZnO films grown by atomic layer deposition

In situ transmission electron microscopy of resistive switching in thin silicon oxide layers

Transmission Electron Microscopy on Memristive Devices: An Overview

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