Investigation of HfO2 and ZrO2 for Resistive Random Access Memory applications

Salaün, A.; Grampeix, H.; Buckley, J.; Mannequin, C.; Vallée, C.; Gonon, P.; Jeannot, S.; Gaumer, C.; Gros-Jean, M.; Jousseaume, V.

doi:10.1016/j.tsf.2012.10.070

Cited by 29 publications

(19 citation statements)

References 17 publications

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“…6 However, the thermal stability of HfO 2 thin film is a serious issue for memory characteristics due to the low crystallization temperature (<400 • C). 12 The RRAM devices with crystalline phase HfO 2 film suffer the RS behaviors variation due to location dependent conductive filament (CF) formation. For example, if CF grows along the grain boundaries of polycrystalline HfO 2 film, low forming voltage and good RS behaviors are observed, whereas high forming voltage is detected in amorphous phase and crystalline phase HfO 2 RRAM devices.…”

mentioning

confidence: 99%

Improved Resistive Switching Characteristics by Al2O3 Layers Inclusion in HfO2-Based RRAM Devices

Huang

Jieng

Jang

et al. 2013

ECS Solid State Letters

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A series of complex HfO 2 /Al 2 O 3 layer by layer resistive random access memory(RRAM) structure grown by atomic layer deposition are investigated. The modulation of forming voltage can be achieved by controlling the number of Al 2 O 3 layers in HfO 2 devices. In addition, the crystallization temperature of HfO 2 based RRAM devices can also be improved by insetting Al 2 O 3 layers in HfO 2 film. Compared with pure HfO 2 device, a significant improvement in resistive switching properties such as forming voltage variation and the distribution of HRS/LRS during resistance switching is demonstrated in the HfO 2 /Al 2 O 3 layer by layer devices. Moreover, good endurance characteristic and highly reliable multibit operation are also achieved in this device structure.Resistive random access memory (RRAM) is a promising candidate to replace the currently flash memory device due to its simple structure, low voltage operation, high scalability, and multibit data storage. 1,2 It is found that transition metal oxides (TMOs) can be utilized in RRAM devices, such as ZrO 2 , 3,4 NiO, 5 and HfO 2 . 6-11 Among those various TMOs, HfO 2 is one of the appealing materials that had considerable attention owing to its high dielectric constant (k), superior resistive switching (RS) performance, and compatible standard complementary metal oxide semiconductor (CMOS) technology process. 6 However, the thermal stability of HfO 2 thin film is a serious issue for memory characteristics due to the low crystallization temperature (<400 • C). 12 The RRAM devices with crystalline phase HfO 2 film suffer the RS behaviors variation due to location dependent conductive filament (CF) formation. For example, if CF grows along the grain boundaries of polycrystalline HfO 2 film, low forming voltage and good RS behaviors are observed, whereas high forming voltage is detected in amorphous phase and crystalline phase HfO 2 RRAM devices. 7 On the other hand, crystalline phase HfO 2 film, which is stoichiometric structure, prevents creating enough oxygen vacancies in RRAM devices for RS behaviors. 8 Moreover, the high forming voltage crystalline phase HfO 2 film may cause RRAM devices hard breakdown during forming process. Besides, for the scaled RRAM devices, the larger non-uniformity grain boundaries for cell by cell with crystalline phase HfO 2 film will cause the variation of device performance. 9 Therefore, the amorphous phase HfO 2 exhibiting uniformity film quality is suitable for RRAM development. According to previous literature, the RS behaviors are dependent on the degree of crystalline of HfO 2 film, which critically influences the device yield. Hence, this phenomenon of low crystallization temperature in HfO 2 is not allowed existence in further RRAM applications.In this letter, we fabricate Hf x Al y O films, which are the architecture with a series of complex HfO 2 /Al 2 O 3 layer by layer structure by using atomic layer deposition system (ALD), for HfO 2 -based RRAM devices. Here, we show the insetting Al 2 O 3 layers would significantly in...

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confidence: 99%

Improved Resistive Switching Characteristics by Al2O3 Layers Inclusion in HfO2-Based RRAM Devices

Huang

Jieng

Jang

et al. 2013

ECS Solid State Letters

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“…By inserting Eq. (15) in the model of Beaumont and Jacobs 17 for electrode polarization in solids, we showed that 4…”

Section: Electrode Polarization Related To Hopping Conductionmentioning

confidence: 69%

“…15 As for HfO 2 films, increasing the ac voltage in the volt range leads to C increase in the 10% range ( Fig. 7(a)).…”

Section: Generalization To Ald-deposited High-k Oxidesmentioning

confidence: 76%

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Differences between direct current and alternating current capacitance nonlinearities in high-k dielectrics and their relation to hopping conduction

Khaldi

Gonon

Vallée

et al. 2014

Journal of Applied Physics

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Articles you may be interested inDetermination of the density of the defect states in Hf0.5Zr0.5O2 high-k film Deposited by using rf-magnetron sputtering technique AIP Advances 4, 087114 (2014); 10.1063/1.4892857An investigation of capacitance-voltage hysteresis in metal/high-k/In0.53Ga0.47As metal-oxide-semiconductor capacitors Modeling of nonlinearities in the capacitance-voltage characteristics of high-k metal-insulator-metal capacitors Capacitance nonlinearities were studied in atomic layer deposited HfO 2 films using two types of signals: a pure ac voltage of large magnitude (ac nonlinearities) and a small ac voltage superimposed to a large dc voltage (dc nonlinearities). In theory, ac and dc nonlinearities should be of the same order of magnitude. However, in practice, ac nonlinearities are found to be an order of magnitude higher than dc nonlinearities. Besides capacitance nonlinearities, hopping conduction is studied using low-frequency impedance measurements and is discussed through the correlated barrier hopping model. The link between hopping and nonlinearity is established. The ac nonlinearities are ascribed to the polarization of isolated defect pairs, while dc nonlinearities are attributed to electrode polarization which originates from defect percolation paths. Both the ac and dc capacitance nonlinearities display an exponential variation with voltage, which results from field-induced lowering of the hopping barrier energy. V C 2014 AIP Publishing LLC.

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“…the monoclinic ( m ), tetragonal ( t ), cubic ( c ), and orthorhombic ( o ) form . Zirconia films in RS devices are generally nano‐crystalline in as‐deposited state or after annealing prior to the investigation . Therefore, a treatment of the ZrO 2 thin films as a perfect crystalline bulk material might be insufficient for an understanding of the RS properties of the ZrO 2 based devices.…”

Section: Introductionmentioning

confidence: 99%

Impedance spectroscopy study of the unipolar and bipolar resistive switching states of atomic layer deposited polycrystalline ZrO₂ thin films

Kärkkänen

Shkabko

Heikkilä

et al. 2015

Physica Status Solidi (a)

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The polarity of the resistive switching (RS) characteristic of metal‐oxide‐metal devices from atomic layer deposited polycrystalline ZrO2 films was studied by means of impedance spectroscopy. Pt/ZrO2/Ti/Pt cells made with 10 nm Ti and 30 nm Pt capping top electrodes, served as unipolar switching (US) devices. Bipolar switching (BS) devices were represented by Pt/ZrO2/30 nm TiN cells. Temperature measurements of the ON‐state resistances clearly show metallic and semiconducting behavior for the US and BS cells, respectively. The pristine and the ON and OFF states of the devices were analyzed by means of impedance spectroscopy. All ZrO2 based RS devices exhibited similar impedance characteristics in the pristine states. In contrast, after electroforming clear differences in the Nyquist‐plots of the US and BS devices were observed. The effect of the device structure on the RS polarity is discussed under consideration of the pillar‐shaped grainy microstructure of the ZrO2 thin films. An empirical model based on redox reactions between ZrO2 and the non‐noble metal electrode is proposed emphasizing defect formation prior at the ZrO2 grain boundaries.

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Investigation of HfO2 and ZrO2 for Resistive Random Access Memory applications

Cited by 29 publications

References 17 publications

Improved Resistive Switching Characteristics by Al2O3 Layers Inclusion in HfO2-Based RRAM Devices

Improved Resistive Switching Characteristics by Al2O3 Layers Inclusion in HfO2-Based RRAM Devices

Differences between direct current and alternating current capacitance nonlinearities in high-k dielectrics and their relation to hopping conduction

Impedance spectroscopy study of the unipolar and bipolar resistive switching states of atomic layer deposited polycrystalline ZrO₂ thin films

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Investigation of HfO2 and ZrO2 for Resistive Random Access Memory applications

Cited by 29 publications

References 17 publications

Improved Resistive Switching Characteristics by Al2O3 Layers Inclusion in HfO2-Based RRAM Devices

Improved Resistive Switching Characteristics by Al2O3 Layers Inclusion in HfO2-Based RRAM Devices

Differences between direct current and alternating current capacitance nonlinearities in high-k dielectrics and their relation to hopping conduction

Impedance spectroscopy study of the unipolar and bipolar resistive switching states of atomic layer deposited polycrystalline ZrO2 thin films

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Impedance spectroscopy study of the unipolar and bipolar resistive switching states of atomic layer deposited polycrystalline ZrO₂ thin films