Impact of Zr addition on properties of atomic layer deposited HfO2

Triyoso, Dina H.; Hegde, Rama I.; Schaeffer, J. K.; Roan, D.; Tobin, Philip J.; Samavedam, S.; White, Bruce; Gregory, R.; Wang, X.-D.

doi:10.1063/1.2208558

Cited by 93 publications

(75 citation statements)

References 12 publications

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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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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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“…10 nicely supported by XRD analysis that the ZrO 2 clusters are predominantly found in the tetragonal phase, which is the most stable form of ZrO 2 that also exhibits the desired maximum dielectric permittivity. 11 Our observation shows that the ZrO 2 clusters are in the tetragonal phase when embedded in La 2 O 3 at lower molecular percentages. This is because the surface free energy of the tetragonal phase is lower to that of monoclinic phase in ZrO 2 clusters with dimensions lower than 30 nm.…”

mentioning

confidence: 76%

Spontaneous nanoclustering of ZrO2 in atomic layer deposited LayZr1−yOx thin films

Jinesh¹,

Tois²,

Klootwijk

et al. 2008

Applied Physics Letters

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“…[26] For atomic layer deposited Hf x Zr 1−x O 2 films a tetragonal phase cannot be observed until the ZrO 2 content is larger than 50%. [27] On p-type (100) Si/SiO 2 the Y-doped HfO 2 thin films were grown using liquid injection metal organic chemical vapor deposition, where the cubic structure of HfO 2 is stabilized for 6.5 at.%. [28] But on GaAs (001) the cubic HfO 2 phase is obtained with 19 at.% Y 2 O 3 using molecular beam epitaxy.…”

Section: Resultsmentioning

confidence: 99%

Stabilization of cubic structure in Mn-doped hafnia

Gao

Zhou

Feng

et al. 2012

Ceramics International

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The compounds Hf1−xMnxO 2−δ (x = 0 ∼ 0.5) have been synthesized by conventional solid state reaction method in Ar. Rietveld analysis of X-ray diffraction data has shown that the Mn-doped HfO2 undergoes a structural transformation from monoclinic to cubic phases, which is significantly dependent on the Mn content under current synthesis conditions. The stabilized cubic structure by multivalent Mn ion doping can transform to the monoclinic structure when annealed at high temperature in air. Transmission electron microscopy and electron diffraction investigations have also confirmed the existence of the high-temperature cubic structure. A mechanism of stabilizing the high-temperature cubic phase in the Hf1−xMnxO 2−δ system has been analyzed based on considerations of manganese substitution effect for hafnium ions and oxygen vacancy formation.

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Impact of Zr addition on properties of atomic layer deposited HfO2

Cited by 93 publications

References 12 publications

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

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

Spontaneous nanoclustering of ZrO2 in atomic layer deposited LayZr1−yOx thin films

Stabilization of cubic structure in Mn-doped hafnia

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