Alternative high-k dielectrics for semiconductor applications

Elshocht, Sven Van; Adelmann, Christoph; Clima, Sergiu; Pourtois, G.; Conard, Thierry; Delabie, Annelies; Franquet, Alexis; Meersschaut, Johan; Menou, N.; Popovici, M.; Richard, Olivier; Schram, T.; Wang, X. P.; Hardy, An; Dewulf, Daan; Bael, Marlies K. Van; Lehnen, P.; Blomberg, Tom; Pierreux, Dieter; Swerts, Johan; Maes, Jan Willem; Wouters, Dirk J.; Gendt, Stefan De; Kittl, J. A.

doi:10.1116/1.3025855

Cited by 15 publications

(13 citation statements)

References 31 publications

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“…From XRR, the mass density of the films was determined, which suffered from a relatively large uncertainty ͑much more than the XRR thickness͒ due to a relatively large surface roughness, and values of 11Ϯ 1 g/ cm 3 and 10Ϯ 1 g/ cm 3 could be estimated for the thermal and plasma-assisted ALD films, respectively. From the combination of RBS results and thickness from XRR, more accurate values yielded a mass density of 12.2Ϯ 0.5 g / cm 3 for thermal ALD and 11.7Ϯ 0.5 g / cm 3 for plasma-assisted ALD.…”

Section: Resultsmentioning

confidence: 99%

“…9 For STO, the method has already shown promise to keep a low leakage current ͑ϳ1 ϫ 10 −8 A / cm 2 ͒ and a low EOT value ͑1.5 nm͒. 10 In the past years, numerous metalorganic precursors, such as Ru͑thd͒ 3 , 11 Ru͑acac͒ 3 , 12,13 RuCp 2 , 12,14-17 and Ru͑EtCp͒ 2 , [17][18][19] have been used with O 2 gas for Ru ALD. Employing RuCp 2 , Aaltonen et al 20 showed that these processes rely on the ability of Ru to dissociatively chemisorb O 2 , providing atomic O necessary for the oxidation of the precursor ligands.…”

Section: Introductionmentioning

confidence: 99%

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Atomic layer deposition of Ru from CpRu(CO)2Et using O2 gas and O2 plasma

Leick

Verkuijlen

Lamagna

et al. 2011

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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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. Link to publication General rightsCopyright 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.• 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. The metalorganic precursor cyclopentadienylethyl͑dicarbonyl͒ruthenium ͑CpRu͑CO͒ 2 Et͒ was used to develop an atomic layer deposition ͑ALD͒ process for ruthenium. O 2 gas and O 2 plasma were employed as reactants. For both processes, thermal and plasma-assisted ALD, a relatively high growth-per-cycle of ϳ1 Å was obtained. The Ru films were dense and polycrystalline, regardless of the reactant, yielding a resistivity of ϳ16 ⍀ cm. The O 2 plasma not only enhanced the Ru nucleation on the TiN substrates but also led to an increased roughness compared to thermal ALD.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Atomic layer deposition of Ru from CpRu(CO)2Et using O2 gas and O2 plasma

Leick

Verkuijlen

Lamagna

et al. 2011

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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“…8 For these reasons STO appears to be the favorite candidate as dielectric material due to its high permittivity and its relatively low crystallization temperature (∼550…”

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confidence: 99%

Plasma-Assisted Atomic Layer Deposition of SrTiO₃: Stoichiometry and Crystallinity Studied by Spectroscopic Ellipsometry

Longo

Leick

Roozeboom

et al. 2012

ECS J. Solid State Sci. Technol.

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Strontium titanate (SrTiO3, STO) films were deposited by plasma-assisted ALD using cyclopentadienyl-based Sr- and Ti-precursors with O2 plasma as the oxidizing agent. Spectroscopic ellipsometry (SE) was employed to determine the thickness and the optical properties of the layers. As determined from Rutherford backscattering spectrometry (RBS), [Sr]/([Sr]+[Ti]) ratios ranging from 0.42 to 0.68 were achieved for 30–40 nm thick films by tuning the [SrO]/[TiO2] ALD cycle ratio. Films deposited at 250°C were amorphous and required post-deposition annealing to crystallize into the ultrahigh-k perovskite structure. The crystallinity of the films after rapid thermal annealing strongly depended on the film composition as observed by X-ray diffraction measurements. Using RBS data for a set of as-deposited samples, an optical constant library was built to determine the film stoichiometry from SE directly for the amorphous as-deposited films. After rapid thermal annealing the crystalline phase could be determined from the position of critical points of the measured dielectric function and the estimation of the stoichiometry was also possible for crystallized layers. These results open up a new way to use SE as a real-time characterization method to monitor and tune the STO film composition and crystallinity.

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“…Schematically it is shown in the inset of Fig. 22 After annealing the samples, top Au electrodes were evaporated through the shadow mask to form MIM struc-tures in order to extract the electrical properties. The stack was then annealed at 600 C in order to crystallize the SrTiO 3 layer.…”

Section: A Al 2 O 3 /Srtio 3 Systemmentioning

confidence: 99%

Properties of stacked SrTiO3/Al2O3 metal–insulator–metal capacitors

Lukosius¹,

Wenger²,

Blomberg³

et al. 2012

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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Articles you may be interested inVoltage linearity modulation and polarity dependent conduction in metal-insulator-metal capacitors with atomiclayer-deposited Al2O3/ZrO2/SiO2 nano-stacks Influence of precursor chemistry and growth temperature on the electrical properties of SrTiO 3 -based metalinsulator-metal capacitors grown by atomic layer deposition J. Vac. Sci. Technol. B 29, 01AC04 (2011); 10.1116/1.3525280 Impact of crystallization behavior of Sr x Ti y O z films on electrical properties of metal-insulator-metal capacitors with TiN electrodes Appl. Phys. Lett. 97, 162906 (2010); 10.1063/1.3505323 Atomic-layer-deposited Al 2 O 3 -Hf O 2 -Al 2 O 3 dielectrics for metal-insulator-metal capacitor applications Appl. Phys. Lett. 87, 053501 (2005); 10.1063/1.2005397Low temperature crystallization of high permittivity Ta oxide using an Nb oxide thin film for metal/insulator/metal capacitors in dynamic random access memory applicationsThe possibilities to grow thin films of SrTiO 3 and Al 2 O 3 by atomic layer deposition for stacked metal-insulator-metal capacitors have been investigated in this work. In order to tune the functional properties of the capacitors, different processing steps have been employed to realize different combinations of the dielectric stacks. Electrical properties, extracted after the postdeposition annealing and sputter deposition of the Au top electrodes, indicated that the metal-insulator-metal (MIM) structures with additional Al 2 O 3 layer provided better leakage currents densities, compared to the ones with single SrTiO 3 based MIM capacitors, but the dielectric constant values have also decreased if additional Al 2 O 3 film was inserted. Attempts to optimize the properties of the MIM stacks have been done by manufacturing heterostructures of Al 2 O 3 /SrTiO 3 /Al 2 O 3 as well as SrTiO 3 /Al 2 O 3 /SrTiO 3 . In the first case, Al 2 O 3 prevented the crystallization of SrTiO 3 in the multilayer dielectric structure and therefore reduced the total capacitance density of the particular MIM stack, whereas the SrTiO 3 /Al 2 O 3 /SrTiO 3 stack was found to possess superior electrical properties. Leakage current density as low as $10 À8 A/cm 2 at 2 V and the dielectric constant value of 40 have been extracted.

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Alternative high-k dielectrics for semiconductor applications

Cited by 15 publications

References 31 publications

Atomic layer deposition of Ru from CpRu(CO)2Et using O2 gas and O2 plasma

Atomic layer deposition of Ru from CpRu(CO)2Et using O2 gas and O2 plasma

Plasma-Assisted Atomic Layer Deposition of SrTiO₃: Stoichiometry and Crystallinity Studied by Spectroscopic Ellipsometry

Properties of stacked SrTiO3/Al2O3 metal–insulator–metal capacitors

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Alternative high-k dielectrics for semiconductor applications

Cited by 15 publications

References 31 publications

Atomic layer deposition of Ru from CpRu(CO)2Et using O2 gas and O2 plasma

Atomic layer deposition of Ru from CpRu(CO)2Et using O2 gas and O2 plasma

Plasma-Assisted Atomic Layer Deposition of SrTiO3: Stoichiometry and Crystallinity Studied by Spectroscopic Ellipsometry

Properties of stacked SrTiO3/Al2O3 metal–insulator–metal capacitors

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Plasma-Assisted Atomic Layer Deposition of SrTiO₃: Stoichiometry and Crystallinity Studied by Spectroscopic Ellipsometry