Quantum-size effects in hafnium-oxide resistive switching

Long, Shibing; Lian, Xiaojuan; Cagli, C.; Cartoixà, Xavier; Rurali, Riccardo; Miranda, E.; Jiménez, David; Perniola, L.; Liu, Ming; Suñé, J.

doi:10.1063/1.4802265

Cited by 158 publications

(138 citation statements)

References 23 publications

(23 reference statements)

Supporting

Mentioning

129

Contrasting

Unclassified

Order By: Relevance

“…In these on-states a linear oxygen vacancy filament is simulated by removing one adjacent oxygen atom from each of the nine HfO 2 layers. This linear filament model of oxygen vacancy is similar to that adopted for monoclinic HfO 2 (mHfO 2 ) to study the quantized conductance observed for HfO 2 [8]. The nine removed oxygen atoms are either simply taken out of device, simulating the oxygenescaped state (see Table II), or placed at the interface between electrode and HfO 2 ("O at interface" in Table II), or distributed inside the electrode ("O inside electrode" in Table II).…”

Section: Resultsmentioning

confidence: 99%

“…However, characterization of the whole MIM device with atomic resolution is in general difficult [6] and has not been performed in previous works on HfO 2 -TiN [3,4,7,8]. In this work, we perform first-principles modeling to elucidate the effects of a thin tantalum layer inserted between the TiN cathode and the HfO 2 oxide layer in TiN-HfO 2 heterostructures.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The effect of a Ta oxygen scavenger layer on HfO₂-based resistive switching behavior: thermodynamic stability, electronic structure, and low-bias transport

Zhong

Rungger

Zapol

et al. 2016

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

Reversible resistive switching between high-resistance and low-resistance states in metal-oxidemetal heterostructures makes them very interesting for applications in random access memories. While recent experimental work has shown that inserting a metallic "oxygen scavenger layer" between the positive electrode and oxide improves device performance, the fundamental understanding of how the scavenger layer modifies heterostructure properties is lacking. We use density functional theory to calculate thermodynamic properties and conductance of TiN/HfO2/TiN heterostructures with and without Ta scavenger layer. First, we show that Ta insertion lowers the formation energy of low-resistance states. Second, while the Ta scavenger layer reduces the Schottky barrier height in the high-resistance state by modifying the interface charge at the oxide-electrode interface, the heterostructure maintains a high resistance ratio between high-and low-resistance states. Finally, we show that the low-bias conductance of device on-states becomes much less sensitive to the spatial distribution of oxygen removed from the HfO2 in the presence of the Ta layer. By providing fundamental understanding of the observed improvements with scavenger layers, we open a path to engineer interfaces with oxygen scavenger layers to control and enhance device performance. In turn, this may enable the realization of a non-volatile low-power memory technology with concomitant reduction in energy consumption by consumer electronics and significant benefits to society. energy consumption by consumer electronics and significant benefits to society.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The effect of a Ta oxygen scavenger layer on HfO₂-based resistive switching behavior: thermodynamic stability, electronic structure, and low-bias transport

Zhong

Rungger

Zapol

et al. 2016

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…In recent years, observation of quantized conductance discrete steps characterized by integer or half integer multiples of G 0 5 2e 2 /h has been reported in ECMs 8,[12][13][14][15][16][17][18] and VCMs. [19][20][21][22][23] While there is a few studies on the conductance quantization effect in TCMs, 14,24 we have reported that a conductive filament including a quantum point contact (QPC) can be formed in Pt/NiO/Pt RS cells. by initial voltage sweeping in the cells.…”

Section: Introductionmentioning

confidence: 99%

Appearance of quantum point contact in Pt/NiO/Pt resistive switching cells

2017

View full text Add to dashboard Cite

A resistive switching (RS) phenomenon, namely reversible transitions between the low and high resistance states after forming process, is caused by the formation and rupture of a conductive filament. We confirmed that conductive filaments including a quantum point contact (QPC) in Pt/NiO/Pt RS cells were formed by semiforming, the first step of the forming process. In this study, we examine correlation between microscopic structures in NiO layers and forming characteristics in the Pt/NiO/Pt cells. The appearance condition of the quantized conductance is considered to be associated with the composition ratio of O to Ni of either equivalent to or larger than a critical value. Furthermore, we proposed a RS model based on the forming characteristics especially obtained from the RS cells with different size. Defects which act as the source of a conductive filament including a QPC by semiforming may be randomly distributed in a NiO layer according to Poisson statistics.

show abstract

“…When two oxygen atoms simultaneously block the filament, the device conductance shows a large variation over several orders of magnitude. Our work explains the evolution of conductance observed experimentally 6 , and provides a detailed atomistic mechanism for the set/reset process. Furthermore, PDOS at the Fermi energy depends sensitively on the channel length and QW lengths.…”

Section: Resultsmentioning

confidence: 96%

“…6, the low-resistance states have a large conductance of about 10 2 G 0 , signaling conducting filaments with a large diameter and many conducting channels. During the reset process the conductance is at first reduced to one or a few G 0 , which shows that many of the channels are pinched off and the device is entering a one-dimensional quantum regime.…”

Section: A Calculated Device Conductance and Comparison With Experimmentioning

confidence: 99%

Oxygen-modulated quantum conductance for ultrathin HfO2 -based memristive switching devices

et al. 2016

View full text Add to dashboard Cite

Memristive switching devices, candidates for resistive random access memory technology, have been shown to switch off through a progression of states with quantized conductance and subsequent non-integer conductance (in terms of conductance quantum G 0 ). We have performed calculations based on density functional theory to model the switching process for a Pt-HfO 2 -Pt structure, involving the movement of one or two oxygen atoms. Oxygen atoms moving within a conductive oxygen vacancy filament act as tunneling barriers, and partition the filament into weakly coupled quantum wells. We show that the low-bias conductance decreases exponentially when one oxygen atom moves away from interface. Our results demonstrate the high sensitivity of the device conductance to the position of oxygen atoms.

show abstract

Quantum-size effects in hafnium-oxide resistive switching

Cited by 158 publications

References 23 publications

The effect of a Ta oxygen scavenger layer on HfO₂-based resistive switching behavior: thermodynamic stability, electronic structure, and low-bias transport

The effect of a Ta oxygen scavenger layer on HfO₂-based resistive switching behavior: thermodynamic stability, electronic structure, and low-bias transport

Appearance of quantum point contact in Pt/NiO/Pt resistive switching cells

Oxygen-modulated quantum conductance for ultrathin HfO2 -based memristive switching devices

Contact Info

Product

Resources

About

Quantum-size effects in hafnium-oxide resistive switching

Cited by 158 publications

References 23 publications

The effect of a Ta oxygen scavenger layer on HfO2-based resistive switching behavior: thermodynamic stability, electronic structure, and low-bias transport

The effect of a Ta oxygen scavenger layer on HfO2-based resistive switching behavior: thermodynamic stability, electronic structure, and low-bias transport

Appearance of quantum point contact in Pt/NiO/Pt resistive switching cells

Oxygen-modulated quantum conductance for ultrathin HfO2 -based memristive switching devices

Contact Info

Product

Resources

About

The effect of a Ta oxygen scavenger layer on HfO₂-based resistive switching behavior: thermodynamic stability, electronic structure, and low-bias transport

The effect of a Ta oxygen scavenger layer on HfO₂-based resistive switching behavior: thermodynamic stability, electronic structure, and low-bias transport