Properties of Plasma-Enhanced Atomic Layer Deposition-Grown Tantalum Carbonitride Thin Films

Hoßbach, Christoph; Teichert, S.; Thomas, Jürgen; Wilde, L.; Wojcik, H.; Schmidt, D.; Adolphi, B.; Bertram, M.; Mühle, Uwe; Albert, Matthias; Menzel, S.; Hintze, B.; Bartha, Johann W.

doi:10.1149/1.3205457

Cited by 20 publications

(13 citation statements)

References 41 publications

(51 reference statements)

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“…Elers et al proposed in a 2002 patent the use of metal halides together with a boron-, silicon-, or phosphorus-containing carbon source (e.g., triethylborane) as route to ALD of numerous transition metal carbide films . However, to date, published reports of transition metal carbide ALD have examined the synthesis of a limited selection of materials: tungsten carbide (WC x ), tungsten carbo-nitride (WN x C y ), and tantalum carbo-nitride (TaN x C y ). − …”

Section: Introductionmentioning

confidence: 99%

Atomic Layer Deposition of Amorphous Niobium Carbide-Based Thin Film Superconductors

Klug¹,

Proslier²,

Elam³

et al. 2011

J. Phys. Chem. C

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Section: Introductionmentioning

confidence: 99%

Atomic Layer Deposition of Amorphous Niobium Carbide-Based Thin Film Superconductors

Klug¹,

Proslier²,

Elam³

et al. 2011

J. Phys. Chem. C

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“…However, with the use of H 2 plasma in ALD of TaN, a large variation in composition and resistivity of the films has been reported in the literature. [7][8][9][10][11][12][13] To understand the relation between plasma processes and the material properties, a more detailed insight into the reaction mechanism is needed.…”

Section: Introductionmentioning

confidence: 99%

Reaction mechanisms of atomic layer deposition of TaNx from Ta(NMe2)5 precursor and H2-based plasmas

Knoops

Langereis

Sanden

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 reaction mechanisms of plasma-assisted atomic layer deposition (ALD) of TaN x using Ta(NMe 2 ) 5 were studied using quadrupole mass spectrometry (QMS). The fact that molecule dissociation and formation in the plasma have to be considered for such ALD processes was illustrated by the observation of 4% NH 3 in a H 2 -N 2 (1:1) plasma. Using QMS measurements the reaction products during growth of conductive TaN x using a H 2 plasma were determined. During the Ta(NMe 2 ) 5 exposure the reaction product HNMe 2 was detected. The amount of adsorbed Ta(NMe 2 ) 5 and the amount of HNMe 2 released were found to depend on the number of surface groups generated during the plasma step. At the beginning of the plasma exposure step the molecules HNMe 2 , CH 4 , HCN, and C 2 H 2 were measured. After an extended period of plasma exposure, the reaction products CH 4 and C 2 H 2 were still present in the plasma. This change in the composition of the reaction products can be explained by an interplay of aspects including the plasma-surface interaction, the ALD surface reactions, and the reactions of products within the plasma. The species formed in the plasma (e.g., CH x radicals) can re-deposit on the surface and influence to a large extent the TaN x material composition and properties.

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“…13,16,17,19,22 Although N 2 plasma 12 or NH 3 plasma 15 was used to reduce PDMAT, the resulting film was Ta 3 N 5 , whose resistivity was too high to be measured. Only when the H 2 -based plasma such as H 2 or methane/H 2 or Ar/H 2 plasma 6,12,17,20,22,23 was used as a reactant, highly conductive Ta-based nitride film, actually TaC x N y could be deposited, where the C or N content in the film could be controlled by the deposition conditions, such as growth temperature, plasma condition, and type of reactant. Although these plasma-enhanced ALD (PEALD)-TaC x N y films could be successfully used as a diffusion barrier against Cu, 12,14,20 they have some limitations as metal gate material in n-MOSFET (ntype metal-oxide-semiconductor field effect transistor) because the existence of nitrogen in metal carbide gates tends to increase the work function.…”

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confidence: 99%

“…Only when the H 2 -based plasma such as H 2 or methane/H 2 or Ar/H 2 plasma 6,12,17,20,22,23 was used as a reactant, highly conductive Ta-based nitride film, actually TaC x N y could be deposited, where the C or N content in the film could be controlled by the deposition conditions, such as growth temperature, plasma condition, and type of reactant. Although these plasma-enhanced ALD (PEALD)-TaC x N y films could be successfully used as a diffusion barrier against Cu, 12,14,20 they have some limitations as metal gate material in n-MOSFET (ntype metal-oxide-semiconductor field effect transistor) because the existence of nitrogen in metal carbide gates tends to increase the work function. 21,24 Ideally, metals used in n-MOSFET should have effective work functions near 4.1 eV and metals used in p-MOSFET transistors should have effective work functions near 5.2 eV.…”

mentioning

confidence: 99%

Plasma-Enhanced Atomic Layer Deposition of TaCx Films Using Tris(neopentyl) Tantalum Dichloride and H2 Plasma

Kim

Eom

Kim

et al. 2011

Electrochem. Solid-State Lett.

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TaC x films were deposited by plasma-enhanced atomic layer deposition (PEALD) at a wafer temperature of 300 C using a novel nitrogen-free Ta precursor, tris(neopentyl) tantalum dichloride, Ta[CH 2 C(CH 3 ) 3 ] 3 Cl 2 and H 2 plasma as the reactant. Self-limiting film growth was observed with both the precursor and reactant pulsing time. Both X-ray diffraction and electron diffraction analysis consistently showed that a cubic TaC phase formed, even though the film was Ta-rich TaC x (C/Ta ¼ $0.36). The film resistivity decreased with increasing H 2 plasma pulsing time from 900 to 375 X cm. In this study, a performance of TaC x as a diffusion barrier for Cu interconnects was evaluated. The results showed that the structure of Cu (100 nm)/ALD-TaC x (15 nm)/Si was stable after annealing at 650 C for 30 min.Tantalum (Ta)-based thin films, such as Ta, TaN x , TaC x and TaC x N y , have been investigated for decades for semiconductor microelectronic devices applications owing to their excellent properties, such as high electrical conductivity, chemical, mechanical and thermal stability. 1-6 Although the main applications of these materials are as a diffusion barrier for copper metallization, 1-5 they are also considered to be a metal gate with high-permittivity gate dielectrics. 6 For these applications, they need to be deposited uniformly at high aspect ratio (AR) structures with a conformal thickness as the demand for shrinking dimensions is increased. In addition, a deposition technique with high process controllability and large-area uniformity is needed. Atomic layer deposition (ALD) is a viable solution because ALD uses a self-limiting film growth mode through surface-saturated reactions, which enables atomicscale control of the film thickness and composition with excellent step coverage. 7 Currently, ALD of Ta-based films has attracted increasing attention for the preparation of Ta nitrides. The most critical issue in the TaN x -ALD process is to obtain highly conductive TaN films. Ta 3 N 5 , which is nitrogen-rich phase in the Ta-N binary system and a dielectric material, was deposited using TaCl 5 and NH 3 and its resistivity was as high as $200 X cm. 8 highly conductive TaN film can be deposited using an additional reducing agent, such as Zn (Ref. 8) or trimethyl aluminum (TMA), 9 but its resistivity was still high, from $900 to $1300 X cm. Moreover, small amounts of Zn impurities ($4 atom %) can cause severe problems if they diffused into the Si substrate. In addition, the use of inorganic precursors, such as TaCl 5 and TaBr 5 , has the potential problem of the incorporation of corrosive halogen elements in the film, particularly when the deposition temperature is as low as 400 C. 8,9 The successful deposition of low-resistivity TaN (q: 350-610 mX cm) with inorganic precursors of TaCl 5 (Ref. 10) and TaF 5 (Ref. 11) is possible using N 2 / H 2 plasma as a reducing agent of the precursors, in contrast to the highly-resistive Ta 3 N 5 growth by the reaction of TaCl 5 with molecular NH 3 .Ta nitride ALD was also ...

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Properties of Plasma-Enhanced Atomic Layer Deposition-Grown Tantalum Carbonitride Thin Films

Cited by 20 publications

References 41 publications

Atomic Layer Deposition of Amorphous Niobium Carbide-Based Thin Film Superconductors

Atomic Layer Deposition of Amorphous Niobium Carbide-Based Thin Film Superconductors

Reaction mechanisms of atomic layer deposition of TaNx from Ta(NMe2)5 precursor and H2-based plasmas

Plasma-Enhanced Atomic Layer Deposition of TaCx Films Using Tris(neopentyl) Tantalum Dichloride and H2 Plasma

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