Epitaxial growth of TiN films by N-implantation into evaporated Ti films

Kasukabe, Y.; Saito, Noriko; Suzuki, Masahiro; Yamada, Yukio; Fujino, Y.; Nagata, Shinji; Kishimoto, Masashi; Yamaguchi, S.

doi:10.1116/1.581488

Cited by 11 publications

(5 citation statements)

References 27 publications

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“…On the other hand, in the N-implanted Ti films with N/Ti<∼1.0, there coexist both hcp-Ti and TiN y crystallites. And the lattice expansions (strain) due to the occupation of N in the octahedral sites of hcp-Ti and fcc-Ti sublattice of TiN y in the present in-situ observation are observed, which is a reconfirmation of the lattice expansions reported in the ex-situ experiments [14]. Thus, the strain due to the increase in the lattice constant can be considered as one of the driving forces for the hcp-fcc transformation.…”

Section: Methodssupporting

confidence: 88%

“…Titanium films of 100 nm in thickness were deposited on thermally cleaned NaCl (001) surfaces held at RT and 250 • C, respectively, by an electron beam heating method in an ultra high vacuum. Detailed descriptions of the preparation method for deposited Ti films were presented in earlier papers [12][13][14]. The Ti films deposited at RT and 250 • C, separated from NaCl substrates, were respectively heated up to 350 • C at a heating rate of 2 • C/min in a 400 kV TEM combined with ion accelerators at JAEA-Takasaki [15].…”

Section: Methodsmentioning

confidence: 99%

“…Thus, much interest has been focused on the epitaxial films and the atomistic interfacial structures between TiN films and substrates [4,[6][7][8][9][10][11]. It was reported through ex-situ experiments that NaCl-type TiN y films were "epitaxially" grown by Nimplantation into as-deposited Ti films held at room temperature (RT) [12][13][14]. However, ex-situ experiments are known to change the surface composition and structure, and to influence the electronic structure [5].…”

Section: Introductionmentioning

confidence: 99%

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In-situ Observation of Nitriding Processes of Deposited-Ti Thin Films due to Ion Implantation in an Analytical Transmission Electron Microscope

Kasukabe

Chen

Yamamoto

et al. 2011

e-J. Surf. Sci. Nanotechnol.

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Both hcp-Ti and CaF2-type TiHx (x ∼ = 1.5), and only hcp-Ti, with preferred orientations have been deposited on NaCl (001) substrates held at room temperature (RT) and 250 • C, respectively. In order to clarify atomistic growth processes of TiNy films due to the implantation of nitrogen ions (N + 2) with 62 keV into as-deposited Ti films, changes of the concentration of H and/or N atoms in Ti films, and of the crystallographic and electronic structures of the films by heating and by nitriding have been investigated by in-situ transmission electron microscope (TEM) equipped with electron energy loss spectroscopy (EELS), with the aid of molecular orbital calculations. Hydrogen atoms which constitute TiHx in the Ti films deposited at RT are released with heating, and are completely released at 350 • C. The H-released unstable fcc-Ti sublattice is then transformed into hcp-Ti. The energy loss peak due to the plasmon excitation observed by EELS for TiHx shifts to the lower energy side with the decrease in the electron density in the hybridized valence band, which means the release of H atoms from TiHx during heating. On the other hand, the TiNy is epitaxially formed by the N-implantation into the hcp-Ti, through the epitaxial transformation of the hcp-Ti to fcc-Ti sublattice, partially inheriting the atomic arrangement of the hcp-Ti, and accompanying the occupation of O-sites of the transformed fcc-Ti by N atoms. The energy loss peak due to the plasmon excitation during N-implantation into the hcp-Ti films gradually shifts to the higher energy side with the increase in dose of N, which means the increase in the electron density in the hybridized valence band. By comparing the results of EELS with those of Rutherford Backscattering Spectrometry, it is clarified that the maximum concentration of N in Ti films during the N-implantation depends on the implantation temperature. The comparison between the results of EELS and those of the molecular orbital calculations elucidates that the changes of electronic structures near the Fermi level depend on the ratio of N/Ti in the films. Furthermore, taking into account the bonding interaction of Ti sublattices with ligand N atoms, the transformation mechanisms between hcp-Ti and TiNy due to the implantation of N atoms are proposed.

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Section: Methodssupporting

confidence: 88%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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In-situ Observation of Nitriding Processes of Deposited-Ti Thin Films due to Ion Implantation in an Analytical Transmission Electron Microscope

Kasukabe

Chen

Yamamoto

et al. 2011

e-J. Surf. Sci. Nanotechnol.

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“…The reflections indicated by the four-index system and the three-index system with asterisks are obtained from the hcp-Ti and TiH x crystallites, respectively. The growth of both hcp-Ti and TiH x agrees with the results of previous papers [14][15][16]: Ti films deposited on NaCl substrates spontaneously absorbed hydrogen (H) atoms from the interior of the NaCl, and then Fig. 1(a), whereas the 00 · 2 and 01 · 1 reflections in Fig.…”

Section: A Deposited Ti Thin Filmssupporting

confidence: 80%

“…Recently, it was reported that NaCl-type (110)-and (001)-oriented TiN y crystallites were 'epitaxially' grown by the N-implantation into CaF 2 -type (110)-oriented TiH x and (03 · 5)-oriented hcp-Ti in the deposited Ti films held at room temperature (RT), respectively [14][15][16]; here, the term 'epitaxially' is used to denote the situation of partially inheriting the atomic arrangements of unimplanted TiH x and hcp-Ti. However, the detailed 'epitaxial' nitriding processes of Ti films with the domains of TiH x and hcp-Ti during N-implantation, as well as the epitaxial growth processes of (110)-oriented TiH x and (03 · 5)-oriented hcp-Ti in deposited Ti films, have not yet been sufficiently understood.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Deposited and Nitrogen-implanted Titanium Films

Wang

Yamamura

Yamamoto

et al. 2005

e-J. Surf. Sci. Nanotechnol.

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Deposited Ti films and TiN films formed by nitrogen-implantation were investigated by transmission electron microscope (TEM) observation and electron energy loss spectroscopy (EELS). Titanium films in the thickness of 100 nm were deposited by an electron beam heating method onto thermally cleaned NaCl(001) surfaces held at room temperature under ultra-high vacuum. In the deposited Ti films, there coexist mainly (03 · 5)-oriented hcp-Ti and (110)

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