Addition of yttrium into HfO2 films: Microstructure and electrical properties

Dubourdieu, C.; Rauwel, Erwan; Roussel, Hervé; Ducroquet, F.; Holländer, B.; Rossell, Marta D.; Tendeloo, G. Van; Lhostis, S.; Rushworth, S.

doi:10.1116/1.3106627

Cited by 40 publications

(20 citation statements)

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“…7 revealed the presence of an orthorhombic phase, whose phase fraction increases against the monoclinic phase until a full stabilization of the cubic phase is reached for high YO 1.5 content. These findings are in good agreement with data on Y:HfO 2 thin films shown by Rauwel et al 21 and Dubourdieu et al, 22 who observed a possibly orthorhombic phase coexisting with the monoclinic phase until a stable cubic phase is reached. This orthorhombic phase, however, was identified as centrosymmetric Pbca and was seemingly not tested for ferroelectric properties.…”

Section: Resultssupporting

confidence: 82%

“…In addition, recent publications report the existence of a possibly orthorhombic=monoclinic phase mixture that forms prior to complete stabilization of the cubic phase in Y:HfO 2 thin films. 21,22 In this paper we investigate the electronic properties of metastable crystalline phases in Y:HfO 2 thin films, and report the observation of ferroelectricity. We demonstrate that a spontaneous polarization in HfO 2 can be provoked by YO 1.5 admixture, while at the same time easing some of the processing constrains present in the previously published systems.…”

Section: Introductionmentioning

confidence: 99%

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Ferroelectricity in yttrium-doped hafnium oxide

Müller

Schröder

Böscke³

et al. 2011

Journal of Applied Physics

601

351

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Structural incommensurate modulation rule in hexagonal Ba(Ti1-xMx)O3-δ (M = Mn, Fe) multiferroics AIP Advances 2, 042129 (2012) Water assisted gate induced temporal surface charge distribution probed by electrostatic force microscopy J. Appl. Phys. 112, 084329 (2012) Influence of target composition and deposition temperature on the domain structure of BiFeO3 thin films AIP Advances 2, 042104 (2012) Nanodomain structures formation during polarization reversal in uniform electric field in strontium barium niobate single crystals J. Appl. Phys. 112, 064117 (2012) The effect of the top electrode interface on the hysteretic behavior of epitaxial ferroelectric Pb(Zr,Ti)O3 thin films with bottom SrRuO3 electrode J. Appl. Phys. 112, 064116 (2012) Additional information on J. Appl. Phys. Structural and electrical evidence for a ferroelectric phase in yttrium doped hafnium oxide thin films is presented. A doping series ranging from 2.3 to 12.3 mol% YO 1.5 in HfO 2 was deposited by a thermal atomic layer deposition process. Grazing incidence X-ray diffraction of the 10 nm thick films revealed an orthorhombic phase close to the stability region of the cubic phase. The potential ferroelectricity of this orthorhombic phase was confirmed by polarization hysteresis measurements on titanium nitride based metal-insulator-metal capacitors. For 5.2 mol% YO 1.5 admixture the remanent polarization peaked at 24 lC=cm 2 with a coercive field of about 1.2 MV=cm. Considering the availability of conformal deposition processes and CMOS-compatibility, ferroelectric Y:HfO 2 implies high scaling potential for future, ferroelectric memories.

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Section: Resultssupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Ferroelectricity in yttrium-doped hafnium oxide

Müller

Schröder

Böscke³

et al. 2011

Journal of Applied Physics

601

351

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“…Depth resolved XPS measurements demonstrate only signals from Hf and O in the films (not shown) and thus establish that the HiTUS films are free from any elemental impurities. This is important www.pss-b.com since impurities have previously been reported to stabilize metastable HfO 2 polymorphs [30,57,58], and thus the purity of the samples (XPS sensitivity limit <0.1-1%) ensures that the unique film properties are only related to the HiTUS deposition. A Hf:O stoichiometry ratio of 1:2.1 is estimated from XPS.…”

Section: Hitus Filmsmentioning

confidence: 99%

High‐density remote plasma sputtering of high‐dielectric‐constant amorphous hafnium oxide films

Bayer

Hofmann

et al. 2013

Physica Status Solidi (b)

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Hafnium oxide (HfO x ) is a high dielectric constant (k) oxide which has been identified as being suitable for use as the gate dielectric in thin film transistors (TFTs). Amorphous materials are preferred for a gate dielectric, but it has been an ongoing challenge to produce amorphous HfO x while maintaining a high dielectric constant. A technique called high target utilization sputtering (HiTUS) is demonstrated to be capable of depositing high-k amorphous HfO x thin films at room temperature. The plasma is generated in a remote chamber, allowing higher rate deposition of films with minimal ion damage. Compared to a conventional sputtering system, the HiTUS technique allows finer control of the thin film microstructure. Using a conventional reactive rf magnetron sputtering technique, monoclinic nanocrystalline HfO x thin films have been deposited at a rate of $1.6 nm min À1 at room temperature, with a resistivity of 10 13 V cm, a breakdown strength of 3.5 MV cm À1 and a dielectric constant of $18.2. By comparison, using the HiTUS process, amorphous HfO x (x ¼ 2.1) thin films which appear to have a cubic-like short-range order have been deposited at a high deposition rate of $25 nm min À1 with a high resistivity of 10 14 V cm, a breakdown strength of 3 MV cm À1 and a high dielectric constant of $30. Two key conditions must be satisfied in the HiTUS system for high-k HfO x to be produced. Firstly, the correct oxygen flow rate is required for a given sputtering rate from the metallic target. Secondly, there must be an absence of energetic oxygen ion bombardment to maintain an amorphous microstructure and a high flux of medium energy species emitted from the metallic sputtering target to induce a cubiclike short range order. This HfO x is very attractive as a dielectric material for large-area electronic applications on flexible substrates.

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“…1,2 More complex MOS structures including nanolaminates, 3 rare-earth doped stacks, 4 and ternary semiconductors 5 are currently under consideration for future complementary MOS (CMOS) technologies as well. The replacement of Si-based materials will not only allow further scaling down of the devices because of a significant reduction of the gate leakage current, but also enhance their switching speed capability.…”

Section: Introductionmentioning

confidence: 99%

Degradation analysis and characterization of multifilamentary conduction patterns in high-field stressed atomic-layer-deposited TiO2/Al2O3 nanolaminates on GaAs

Miranda

Suñé

Das

et al. 2012

Journal of Applied Physics

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Articles you may be interested inLow-temperature plasma-enhanced atomic layer deposition of HfO2/Al2O3 nanolaminate structure on Si J. Vac. Sci. Technol. B 33, 01A101 (2015); 10.1116/1.4895010 Effects of rapid thermal annealing on the properties of HfO2/La2O3 nanolaminate films deposited by plasma enhanced atomic layer deposition J. Vac. Sci. Technol. A 33, 01A116 (2015); 10.1116/1.4900935 X-ray reflectivity characterization of atomic layer deposition Al2O3/TiO2 nanolaminates with ultrathin bilayers J. Vac. Sci. Technol. A 32, 01A111 (2014); 10.1116/1.4833556 Electrical characteristics of metal-insulator-semiconductor structures with atomic layer deposited Al 2 O 3 , HfO 2 , and nanolaminates on different silicon substrates J. Vac. Sci. Technol. B 29, 01AA07 (2011); 10.1116/1.3532544 Plasma-assisted atomic layer deposition of TiN / Al 2 O 3 stacks for metal-oxide-semiconductor capacitor applicationsIn this paper, the effects of applying a high-field electrical stress on TiO 2 /Al 2 O 3 nanolaminates grown by atomic layer deposition onto a p-type GaAs substrate are investigated. First, it is shown that the current-time (I-t) characteristic of the devices during a constant voltage stress follows the extended Curie-von Schweidler law for dielectric degradation. The application of voltage sweeps from negative to positive bias and back also reveals an hysteretic behavior of the current-voltage (I-V) characteristic typical of the resistive switching mechanism ocurring in these and others high permittivity oxide films. Second, we show that after the detection of the breakdown event the capacitors exhibit a random spot pattern on the top metal electrode (Al) associated with the generation of multifilamentary conduction paths running across the insulating film. The number of generated spots depends on the magnitude of the electrical stress and for a sufficiently large density, it is possible to demonstrate that they are spatially uncorrelated. The analysis is carried out using spatial statistics techniques such as the intensity plot, the interspot distance histogram, and the pair correlation function. V C 2012 American Institute of Physics. [http://dx.

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Addition of yttrium into HfO2 films: Microstructure and electrical properties

Cited by 40 publications

References 80 publications

Ferroelectricity in yttrium-doped hafnium oxide

Ferroelectricity in yttrium-doped hafnium oxide

High‐density remote plasma sputtering of high‐dielectric‐constant amorphous hafnium oxide films

Degradation analysis and characterization of multifilamentary conduction patterns in high-field stressed atomic-layer-deposited TiO2/Al2O3 nanolaminates on GaAs

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