Reduction of leakage currents with nanocrystals embedded in an amorphous matrix in metal-insulator-metal capacitor stacks

Krause, A.; Weber, Walter M.; Schröder, Uwe; Pohl, Darius; Rellinghaus, Bernd; Heitmann, Johannes; Mikolajick, Thomas

doi:10.1063/1.3664395

Cited by 3 publications

(4 citation statements)

References 18 publications

(20 reference statements)

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“…The permittivity values have been extracted from a linear fit of the inverse capacitance over thickness by neglecting any interfacial capacitance. As shown in Figure , the permittivity of CaTiO 3 increases to a value of at least 55 between 10 and 30 nm thickness instead of 28 for an amorphous CaTiO 3 capacitor stack . As depicted in Figure , the constant permittivity indicates a linear increase of crystallization with layer thickness.…”

Section: Embedded Nanocrystallites In An Ultrathin Capacitor Stackmentioning

confidence: 85%

“…As shown in Figure 5, the permittivity of CaTiO 3 increases to a value of at least 55 between 10 and 30 nm thickness instead of 28 for an amorphous CaTiO 3 capacitor stack. 20 As depicted in Figure 5, the constant permittivity indicates a linear increase of crystallization with layer thickness. Therefore, this intermediate permittivity is not caused by an interfacial effect.…”

Section: Embedded Nanocrystallites In Anmentioning

confidence: 95%

“…Capacitors with those embedded nanocrystallites exhibit an intermediate permittivity of 50 and above between the permittivity of approximately 105 in a fully crystalline layer and 28 for amorphous CaTiO 3 layers. 20 Pt is a suitable material for epitaxial growth of perovskites 21,22 with a lattice constant comparable to CaTiO 3 . 23 Besides the good lattice match, the selective growth of the nanocrystallites takes advantage of the different surface energies of CaTiO 3 and Pt facets.…”

Section: Introductionmentioning

confidence: 99%

“…In this work, we show a detailed study of perovskite nanocrystallites surrounded by an amorphous matrix for the case of sputter deposited CaTiO 3 . Capacitors with those embedded nanocrystallites exhibit an intermediate permittivity of 50 and above between the permittivity of approximately 105 in a fully crystalline layer and 28 for amorphous CaTiO 3 layers . Pt is a suitable material for epitaxial growth of perovskites , with a lattice constant comparable to CaTiO 3 .…”

Section: Introductionmentioning

confidence: 99%

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Investigation of Embedded Perovskite Nanoparticles for Enhanced Capacitor Permittivities

Krause

Weber

Pohl

et al. 2014

ACS Appl. Mater. Interfaces

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Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers) Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. Link to publication• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. ABSTRACT: Growth experiments show significant differences in the crystallization of ultrathin CaTiO 3 layers on polycrystalline Pt surfaces. While the deposition of ultrathin layers below crystallization temperature inhibits the full layer crystallization, local epitaxial growth of CaTiO 3 crystals on top of specific oriented Pt crystals occurs. The result is a formation of crystals embedded in an amorphous matrix. An epitaxial alignment of the cubic CaTiO 3 ⟨111⟩ direction on top of the underlying Pt {111} surface has been observed. A reduced forming energy is attributed to an interplay of surface energies at the {111} interface of both materials and CaTiO 3 nanocrystallites facets. The preferential texturing of CaTiO 3 layers on top of Pt has been used in the preparation of ultrathin metal−insulator−metal capacitors with 5−30 nm oxide thickness. The effective CaTiO 3 permittivity in the capacitor stack increases to 55 compared to capacitors with amorphous layers and a permittivity of 28. The isolated CaTiO 3 crystals exhibit a passivation of the CaTiO 3 grain surfaces by the surrounding amorphous matrix, which keeps the capacitor leakage current at ideally low values comparable for those of amorphous thin film capacitors.

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Section: Embedded Nanocrystallites In An Ultrathin Capacitor Stackmentioning

confidence: 85%

Section: Embedded Nanocrystallites In Anmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Investigation of Embedded Perovskite Nanoparticles for Enhanced Capacitor Permittivities

Krause

Weber

Pohl

et al. 2014

ACS Appl. Mater. Interfaces

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Effects of vanadium substitution on the electrical performance of amorphous SrBi2Ta2O9 thin-film capacitors

et al. 2014

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Size- and position-controlled Ge nanocrystals separated by high-k dielectrics

et al. 2022

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Germanium nanocrystals embedded in high-k dielectric matrices are of main interest for infrared sensing application, as a role model for Ge-based nanoelectronics passivation or for nonvolatile memory devices. The capability of the size control of those nanocrystals via rapid thermal processing of superlattice structures is shown for the [Ge–TaZrOx/TaZrOx]n, [Ge–TaZrOx/SiO2/TaZrOx]6, and [TaZrOx/Ge–SiO2]n superlattice systems. All superlattices were deposited by radiofrequency magnetron sputtering. Transmission electron microscopy (TEM) imaging confirms the formation of spherically shaped nanocrystals. Raman scattering proved the crystallization of Ge above 700°C. The TaZrOx crystallizes above 770°C, associated with a phase separation of Ta2O5 and ZrO2 as confirmed by x-ray diffraction. For the composite layers having 3 nm and 6 nm thickness, the size of the Ge nanocrystals correlates with the deposited layer thickness. Thicker composite layers (above 9 nm) form two fractions of nanocrystals with different sizes. An additional SiO2 layer in the [Ge–TaZrOx/SiO2/TaZrOx]6 superlattice stacks facilitates the formation of larger and better separated Ge nanocrystals. The deposition of Ge-SiO2 composite layers separated by pure TaZrOx illustrates the barrier effect of TaZrOx against Ge diffusion. All three material systems allow the controlled formation of Ge nanocrystals in amorphous matrices at temperatures above 700 and below 770°C. Graphical abstract

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Reduction of leakage currents with nanocrystals embedded in an amorphous matrix in metal-insulator-metal capacitor stacks

Cited by 3 publications

References 18 publications

Investigation of Embedded Perovskite Nanoparticles for Enhanced Capacitor Permittivities

Investigation of Embedded Perovskite Nanoparticles for Enhanced Capacitor Permittivities

Effects of vanadium substitution on the electrical performance of amorphous SrBi2Ta2O9 thin-film capacitors

Size- and position-controlled Ge nanocrystals separated by high-k dielectrics

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