Electronic structure of the SiN<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow /><mml:mrow><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>/TiN interface: A model system for superhard nanocomposites

Patscheider, Jörg; Hellgren, Niklas; Haasch, Richard T.; Petrov, I.; Greene, J. E.

doi:10.1103/physrevb.83.125124

Cited by 42 publications

(12 citation statements)

References 43 publications

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“…We select Al as the cap layer for the following reasons: (1) the Al native oxide, <2 nm thick at room temperature, is stable against spallation; 29 thus minimizing interfacial reactions; (3) and Al core-level peaks do not overlap with the primary Ti and N signals. We show that Al layers with thickness d Al ¼ 1.5 nm form a dense continuous, oxidized barrier that protects the TiN underlayer and allows for acquisition of high-resolution Ti 2p and N 1s core-level spectra, with clear pronounced satellite features, [30][31][32][33] which are in excellent agreement with those obtained from epitaxial TiN layers grown in-situ in an XPS system. 34 O 1s spectra reveal no evidence for Ti-O bonding.…”

Section: Introductionsupporting

confidence: 70%

“…30) is widely discussed in the literature. Two primary interpretations have been proposed including a decrease in the screening probability of the core-hole created during photoionization by Ti 3d electrons, 30,32,45 and t 1g ! 2t 2g intraband transitions between occupied and unoccupied electron states near the Fermi level (shake-up events).…”

Section: A Xps Analyses Of Armentioning

confidence: 99%

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Al capping layers for nondestructive x-ray photoelectron spectroscopy analyses of transition-metal nitride thin films

Greczyński¹,

Petrov²,

Greene³

et al. 2015

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

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X-ray photoelectron spectroscopy (XPS) compositional analyses of materials that have been air exposed typically require ion etching in order to remove contaminated surface layers. However, the etching step can lead to changes in sample surface and near-surface compositions due to preferential elemental sputter ejection and forward recoil implantation; this is a particular problem for metal/gas compounds and alloys such as nitrides and oxides. Here, the authors use TiN as a model system and compare XPS analysis results from three sets of polycrystalline TiN/Si(001) films deposited by reactive magnetron sputtering in a separate vacuum chamber. The films are either (1) air-exposed for ≤10 min prior to insertion into the ultrahigh-vacuum (UHV) XPS system; (2) air-exposed and subject to ion etching, using different ion energies and beam incidence angles, in the XPS chamber prior to analysis; or (3) Al-capped in-situ in the deposition system prior to air-exposure and loading into the XPS instrument. The authors show that thin, 1.5–6.0 nm, Al capping layers provide effective barriers to oxidation and contamination of TiN surfaces, thus allowing nondestructive acquisition of high-resolution core-level spectra representative of clean samples, and, hence, correct bonding assignments. The Ti 2p and N 1s satellite features, which are sensitive to ion bombardment, exhibit high intensities comparable to those obtained from single-crystal TiN/MgO(001) films grown and analyzed in-situ in a UHV XPS system and there is no indication of Al/TiN interfacial reactions. XPS-determined N/Ti concentrations acquired from Al/TiN samples agree very well with Rutherford backscattering and elastic recoil analysis results while ion-etched air-exposed samples exhibit strong N loss due to preferential resputtering. The intensities and shapes of the Ti 2p and N 1s core level signals from Al/TiN/Si(001) samples do not change following long-term (up to 70 days) exposure to ambient conditions, indicating that the thin Al capping layers provide stable surface passivation without spallation.

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Section: Introductionsupporting

confidence: 70%

Section: A Xps Analyses Of Armentioning

confidence: 99%

Al capping layers for nondestructive x-ray photoelectron spectroscopy analyses of transition-metal nitride thin films

Greczyński¹,

Petrov²,

Greene³

et al. 2015

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

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“…The TiN/SiNx system has been widely studied 24,23,25,26 for the synthesis of superhard (H > 40 GPa) 27 nanocomposite thin films, with the primary applications being wear-resistant coatings on cutting tools, based upon phase self-organization during film growth. The first report on nanocomposite hardness enhancement, by Li Shizhi et al, 28 was followed by a series of papers by Veprek et al 27,29,30 exploiting high-temperature film growth to provide strong SiNz surface segregation giving rise to a nanostructure consisting of TiN crystallites encapsulated by a few monolayers (ML) of a disordered SiNz tissue phase.…”

Section: Introductionmentioning

confidence: 99%

Control of Ti1−xSixN nanostructure via tunable metal-ion momentum transfer during HIPIMS/DCMS co-deposition

Greczyński

Patscheider

et al. 2015

Surface and Coatings Technology

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“…19 and 21), a decrease in the screening of the core-hole due to photoionization (Refs. 18,20,and 22), and structural effects (Ref. 23).…”

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confidence: 99%

X-ray Photoelectron Spectroscopy Analyses of the Electronic Structure of Polycrystalline Ti1-xAlxN Thin Films with 0 ≤ x ≤ 0.96

Greczyński

Jensen

Greene

et al. 2014

Surface Science Spectra

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Metastable Ti 1-x Al x N (0 x 0.96) alloy thin films are grown by reactive magnetron sputter deposition using a combination of high-power pulsed magnetron (HIPIMS) and DC magnetron sputtering (DCMS). Layers are deposited from elemental Ti and Al targets onto Si(001) substrates at 500C. All Ti 1-x Al x N film surfaces are analyzed by x-ray photoelectron spectroscopy (XPS) employing monochromatic Al K a radiation (h = 1486.6 eV). Prior to spectra acquisition, TiAlN surfaces are sputter-cleaned in-situ with 4 keV Ar + ions incident at an angle of 70 with respect to the surface normal. XPS results reveal satellite structures on the high binding energy side of the Ti 2p, Ti 3s, and Ti 3p core-level signals. The intensities of the primary Ti features (Ti 2p, Ti 3s, and Ti 3p) decrease with increasing AlN concentration such that the satellite peaks dominate spectra from films with x ! 0.67. The density-of-states at the Fermi level also decrease with increasing x indicating that the satellite peaks are due to screening of core holes created by the photoionization event. Film compositions, obtained using XPS sensitivity factors, agree to within . Nevertheless, metastable NaCl-structure pseudobinary alloys can be obtained by physical vapor deposition (PVD) due to kinetically-limited low-temperature growth and low-energy ion-irradiation-induced dynamic mixing in the near-surface region. Reported kinetic AlN solubility limits in cubic Ti 1-x Al x N alloys are typically x max $ 0.50 for dc magnetron sputter (DCMS) deposition at film growth temperatures T s = 500 C (Refs. 8 and 9), while x max values up to 0.66 have been reported using cathodic arc evaporation (Refs. 10 and 11). However, the resulting films have very high compressive stresses, up to À5 GPa (Ref. 12) for DCMS and À9.1 GPa (Ref. 13) for arc-deposited films.Recently, we have shown that single-phase NaCl-structure Ti 1-x Al x N alloys with x 0.64, combining high hardness and low residual stress, can be grown by a hybrid technique consisting of reactive high-power pulsed magnetron sputtering (HIPIMS) of Al and DC magnetron sputtering (DCMS) of Ti targets (Al-HIPIMS/Ti-DCMS) (Refs. 14-16). In distinct contrast, Ti-HIPIMS/Al-DCMS Ti 1-x Al x N layers with x > 0.41 are two-phase mixtures, NaCl-structure Ti 1-x Al x N plus wurtzite AlN, which exhibit low hardness with high compressive stress due to an intense energetic Ti 2+ metal-ion flux incident at the growing film surface.Here, we employ x-ray photoelectron spectroscopy (XPS) to investigate the electronic structure of Ti 1-x Al x N alloy thin films with 0 x 0.96 grown by reactive hybrid Ti-HIPIMS/Al-DCMS co-sputtering. normal. Ti 2p, Ti 3s, Ti 3p, Al 2p, Al 2s, N 1s, and valence band spectra are presented. The Ti 2p core-level spectra exhibit a satellite peak on the high binding energy (BE) side of the Ti 2p 3/2 and Ti 2p 1/2 peaks in agreement with earlier XPS analyses of . The origin of this feature is widely discussed in the literature and several interpretations have been proposed including intra-band transiti...

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Electronic structure of the SiNx/TiN interface: A model system for superhard nanocomposites

Abstract: Nanostructured materials such as nanocomposites and nanolaminates -subjects of intense interest in modern materials research -are defined by internal interfaces, the nature of which is generally unknown. Nevertheless, the interfaces often determine the bulk properties. An

Cited by 42 publications

References 43 publications

Al capping layers for nondestructive x-ray photoelectron spectroscopy analyses of transition-metal nitride thin films

Al capping layers for nondestructive x-ray photoelectron spectroscopy analyses of transition-metal nitride thin films

Control of Ti1−xSixN nanostructure via tunable metal-ion momentum transfer during HIPIMS/DCMS co-deposition

X-ray Photoelectron Spectroscopy Analyses of the Electronic Structure of Polycrystalline Ti1-xAlxN Thin Films with 0 ≤ x ≤ 0.96

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