Interfacial reactions in single-crystal-TiN (100)/Al/polycrystalline-TiN multilayer thin films

Hultman, Lars; Benhenda, S.; Radnóczi, G.; Sundgren, J.‐E.; Greene, J. E.; Petrov, I.

doi:10.1016/0040-6090(92)90430-j

Cited by 51 publications

(25 citation statements)

References 29 publications

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“…48 The ion penetration depth n, which increases with increasing ion energy E Ar þ and decreasing ion incidence angle w, is characterized by the effective depth of collision cascade events, which can be estimated from Monte-Carlo based TRIM simulations of ion/surface interactions, and corresponds to the average TiN primary recoil projected range accounting for straggle. For Ti recoils, n Ti ¼ ¼ À3.3 eV/atom), 29 as well as with earlier studies which show that the Al/TiN interface is stable up to 500 C; [54][55][56] i.e., to a significantly higher temperature than used during Al deposition in the present experiments. TiN oxidation during air exposure is prevented even by the thinnest Al capping layer, d Al ¼ 1.5 nm, indicating that the overlayer is continuous, in agreement with SEM images [see, for example, Fig.…”

Section: Discussionsupporting

confidence: 90%

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: Discussionsupporting

confidence: 90%

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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“…In superlattice systems, the particular crystal structure of AlN layer strongly depends on its layer thickness [20,29]. Cubic structured AlN is stable only when the layer thickness is ≤3.0 nm; for larger thicknesses wurtzite AlN will form [29][30][31][32][33]. It is therefore anticipated that the structure of AlN can be controlled by suitable growth conditions, such as the substrate crystal structure, substrate orientation, and lattice as well as elastic mismatch between the individual layers.…”

Section: Introductionmentioning

confidence: 98%

The effect of interlayer composition and thickness on the stabilization of cubic AlN in AlN/Ti–Al–N superlattices

2014

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“…As AlN has a wide direct electronic band gap of ∼6 eV [19], it can be potentially used in ultraviolet light emitting diodes (LEDs) and laser diodes [20][21][22][23][24][25][26]. At ambient conditions, the stable bulk form of AlN is wurtzite; however under high pressure, phase transitions from wurtzite to zinc blende or rocksalt forms were previously addressed [27][28][29]. Following the theoretical prediction [30], h-AlN was experimentally recently realized by Tsipas et al [31].…”

Section: Introductionmentioning

confidence: 98%

Layer- and strain-dependent optoelectronic properties of hexagonal AlN

et al. 2015

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Motivated by the recent synthesis of layered hexagonal aluminum nitride (h-AlN), we investigate its layerand strain-dependent electronic and optical properties by using first-principles methods. Monolayer h-AlN is a wide-gap semiconductor, which makes it interesting especially for usage in optoelectronic applications. The optical spectra of 1-, 2-, 3-, and 4-layered h-AlN indicate that the prominent absorption takes place outside the visible-light regime. Within the ultraviolet range, absorption intensities increase with the number of layers, approaching the bulk case. On the other hand, the applied tensile strain gradually redshifts the optical spectra. The many-body effects lead to a blueshift of the optical spectra, while exciton binding is also observed for 2D h-AlN. The possibility of tuning the optoelectronic properties via thickness and/or strain opens doors to novel technological applications of this promising material.

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Interfacial reactions in single-crystal-TiN (100)/Al/polycrystalline-TiN multilayer thin films

Cited by 51 publications

References 29 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

The effect of interlayer composition and thickness on the stabilization of cubic AlN in AlN/Ti–Al–N superlattices

Layer- and strain-dependent optoelectronic properties of hexagonal AlN

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