Conduction mechanism of TiN/HfOx/Pt resistive switching memory: A trap-assisted-tunneling model

Yu, Shimeng; Guan, Xialing; Wong, H.-S. Philip

doi:10.1063/1.3624472

Cited by 352 publications

(200 citation statements)

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“…The Schottky or thermionic emission happens when thermally-activated electrons injected over the energy barrier into the conduction band of the oxide as shown in Figure 4 [55]. This type of thermionic emission is one of the most often observed conduction mechanism in oxide especially in relative high temperature [71].…”

Section: Schottky Emissionmentioning

confidence: 99%

“…While CF evolution is typically associated with thermal, electrical or ion migration [19,20], there is no consensus on the dominant conduction mechanism in resistive switching memory devices [21][22][23]. Among the commonly observed conduction mechanisms are: (i) Poole-Frenkel emission [24][25][26][27][28][29][30][31][32]; (ii) Schottky emission [33][34][35][36][37][38][39][40][41][42]; (iii) SCLC [43][44][45][46][47][48][49][50][51][52][53] (iv) trap-assisted tunneling [54][55][56][57][58][59]; and (v) hopping conduction [60][61][62][63][64][65]. To enhance the device performance and data retention property, it is crucial to identifying t...…”

Section: Introductionmentioning

confidence: 99%

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Conduction Mechanism of Valence Change Resistive Switching Memory: A Survey

2015

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Abstract:Resistive switching effect in transition metal oxide (TMO) based material is often associated with the valence change mechanism (VCM). Typical modeling of valence change resistive switching memory consists of three closely related phenomena, i.e., conductive filament (CF) geometry evolution, conduction mechanism and temperature dynamic evolution. It is widely agreed that the electrochemical reduction-oxidation (redox) process and oxygen vacancies migration plays an essential role in the CF forming and rupture process. However, the conduction mechanism of resistive switching memory varies considerably depending on the material used in the dielectric layer and selection of electrodes. Among the popular observations are the Poole-Frenkel emission, Schottky emission, space-charge-limited conduction (SCLC), trap-assisted tunneling (TAT) and hopping conduction. In this article, we will conduct a survey on several published valence change resistive switching memories with a particular interest in the I-V characteristic and the corresponding conduction mechanism.

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Section: Schottky Emissionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Conduction Mechanism of Valence Change Resistive Switching Memory: A Survey

2015

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“…Previous studies suggested that the conduction in HfO 2 based resistive switching memory is dominated by trap-assisted-tunneling process based on the observation that the measured current is insensitive to the temperature change [31][32] and a rise of the AC conductance under high frequency external signal stimulus [33]. The 1/f α noise measured in this work also has a very weak dependence of the temperature (see the Fig.…”

mentioning

confidence: 49%

“…The DC noise current of the resistive switching memory stack is usually attributed to be a random trap/detrap process through the defects such as oxygen vacancies in the CFs [35][36] with a relaxation time τ. The relaxation time, τ, is determined by the transition time for electrode-to-trap tunneling because the trap-to-trap hopping rate is much larger than the electrodeto-trap tunneling rate [32]. The Wentzel-Kramers-Brillouin (WKB) approximation [37] is used to calculate this τ as Eq.…”

mentioning

confidence: 99%

Characterization of low-frequency noise in the resistive switching of transition metal oxide HfO2

Jeyasingh

et al. 2012

Phys. Rev. B

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-Low frequency noise measurements were performed on HfO 2 based bipolar resistive switching memory devices. A 1/f α DC noise power spectral density was observed with α~1 for low resistance state and α~2 for high resistance state. We developed an electron tunneling model to elucidate the conduction process which showed that the 1/f α behavior was due to the distribution of relaxation times of electron tunneling between the electrodes and the traps in the conducting filaments. The transition of the slope index α from 1 to 2 at a certain cutoff frequency indicates that there is a tunneling gap formed between electrodes and the residual of the conductive filaments in the high resistance state.Keywords -low frequency noise, resistive switching (RRAM), transition metal oxide, electron tunneling Currently, transition metal oxide based resistive switching memory is extensively studied as one of the most competitive candidates for future non-volatile memory applications due to its simple structure, fast switching speed, great scalability, and compatibility with silicon complementary metal-oxidesemiconductor (CMOS) technology [9][10][11]. The mechanism of resistive switching phenomenon in oxides is usually attributed to the formation/rupture of conductive filaments (CFs) which may consist of oxygen vacancies or metal precipitates [12]. The set process from high resistance state (HRS) to low resistance state (LRS) is interpreted as a dielectric soft breakdown associated with the migration of oxygen ions toward the anode, leaving behind the oxygen vacancies in the bulk oxide to form CFs connecting both electrodes [13]. To reset from LRS to HRS, there are two modes: in the unipolar reset (the reset occurs at the same polarity as the set), Joule-heating-assisted diffusion of oxygen ions from anode and surrounding oxides rupture the CFs by recombination with oxygen vacancies or re-oxidization of the metal precipitates [14]. In the bipolar reset (the reset occurs at the opposite polarity as the set), electric-field-assisted drift of oxygen ions from the oxygen reservoir rupture the CFs [15]. In the bipolar switching mode, oxidizable electrode materials such as Ti, TiN, TaN are usually used to serve as the oxygen reservoir providing the oxygen ions during the reset process [16]. The device used in this paper exhibits the bipolar switching mode. Although such a phenomenological physical switching picture above has been proposed, the detailed characterization and quantitative theoretical analysis of the conduction mechanism is still lacking in the literature.Low frequency noise (LFN) measurement is a technique that can electrically characterize the trapassisted conduction process in dielectrics [17][18][19] NiO [22] (in this paper f refers to the frequency). In this work, we perform LFN measurement on HfO 2 based resistive switching memory to investigate its conduction and switching mechanism. HfO 2 is chosen because HfO 2 based devices exhibit desirable properties such as ultra-fast switching speed (

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“…A mechanism of TAT through the gap states in TiO 2 was proposed to be responsible for the high tunneling rate of holes. The physical theorem and calculation relevant to TAT have been discussed [25][26][27][28][29]. A multiple trap center model was used to simulate the tunneling current in the SiO 2 .…”

Section: Resultsmentioning

confidence: 99%

Low-Temperature, Chemically Grown Titanium Oxide Thin Films with a High Hole Tunneling Rate for Si Solar Cells

Lee

Lin

et al. 2016

Energies

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Abstract:In this paper, we propose a chemically grown titanium oxide (TiO 2 ) on Si to form a heterojunction for photovoltaic devices. The chemically grown TiO 2 does not block hole transport. Ultraviolet photoemission spectroscopy was used to study the band alignment. A substantial band offset at the TiO 2 /Si interface was observed. X-ray photoemission spectroscopy (XPS) revealed that the chemically grown TiO 2 is oxygen-deficient and contains numerous gap states. A multiple-trap-assisted tunneling (TAT) model was used to explain the high hole injection rate. According to this model, the tunneling rate can be 10 5 orders of magnitude higher for holes passing through TiO 2 than for flow through SiO 2 . With 24-nm-thick TiO 2 , a Si solar cell achieves a 33.2 mA/cm 2 photocurrent on a planar substrate, with a 9.4% power conversion efficiency. Plan-view scanning electron microscopy images indicate that a moth-eye-like structure formed during TiO 2 deposition. This structure enables light harvesting for a high photocurrent. The high photocurrent and ease of production of chemically grown TiO 2 imply that it is a suitable candidate for future low-cost, high-efficiency solar cell applications.

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Conduction mechanism of TiN/HfOx/Pt resistive switching memory: A trap-assisted-tunneling model

Cited by 352 publications

References 20 publications

Conduction Mechanism of Valence Change Resistive Switching Memory: A Survey

Conduction Mechanism of Valence Change Resistive Switching Memory: A Survey

Characterization of low-frequency noise in the resistive switching of transition metal oxide HfO2

Low-Temperature, Chemically Grown Titanium Oxide Thin Films with a High Hole Tunneling Rate for Si Solar Cells

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