Katsuhisa Mukai

Bio: Katsuhisa Mukai is an academic researcher from Kansai University. The author has contributed to research in topics: Ion source & Titanium nitride. The author has an hindex of 3, co-authored 3 publications receiving 57 citations.

Resistivities of titanium nitride films prepared onto silicon by an ion beam assisted deposition method

Abstract: Cubic titanium nitride (TiN) films preferentially oriented to the (200) lattice plane were deposited onto (111) silicon wafers using an ion beam assisted deposition technique with an electron cyclotron resonance ion source for ionizing nitrogen gas and an electron beam evaporator for evaporating Ti metals. The resistivities of the TiN films were inversely proportional to the average size of the crystallites making up the TiN films and decreased with increasing substrate temperature and film thickness. TiN films thicker than 50 nm had resistivities around 30 µ Ω cm, slightly higher than the resistivities of TiN crystals.

Effects of ion beam application on the deposition of low-resistivity titanium nitride films onto silicon

Abstract: Titanium nitride (TiN) films were deposited onto (111) silicon wafers using an ion beam assisted deposition technique employing an electron cyclotron resonance ion source as a means of ionizing the nitrogen gas. The deposited TiN films consisted predominantly of cubic TiN crystals preferentially oriented in the (200) lattice plane, in addition to a small amount of hexagonal TiN and Ti5Si3 crystals. The growth of the Ti5Si3 crystals, however, was restricted to the case where TiN films were deposited with a large fraction of nitrogen ions. The resistivities of the deposited TiN films, which significantly depended upon the fraction of nitrogen ions in the nitrogen beam, decreased with increasing substrate temperature and film thickness. Furthermore, the resistivities of the deposited TiN films were inversely proportional to the average radius of crystallites.

Refractory plasmonics with titanium nitride: broadband metamaterial absorber.

Abstract: A high-temperature stable broadband plasmonic absorber is designed, fabricated, and optically characterized. A broadband absorber with an average high absorption of 95% and a total thickness of 240 nm is fabricated, using a refractory plasmonic material, titanium nitride. This absorber integrates both the plasmonic resonances and the dielectric-like loss. It opens a path for the interesting applications such as solar thermophotovoltaics and optical circuits.

A comparative study of titanium nitride (TiN), titanium oxy nitride (TiON) and titanium aluminum nitride (TiAlN), as surface coatings for bio implants

Abstract: In the present study, the performance of three titanium nitride coatings: TiN, TiON, and TiAlN for biomedical applications were assessed in terms of their surface properties electrochemical corrosion in simulated body fluid and cytotoxicity. Layers of TiN, TiON and TiAlN were deposited onto CP–Ti substrates by DC reactive magnetron sputtering method using a combination of a Ti, Ti–Al targets and an Ar–N 2 mixture discharge gas. The presence of different phases was identified by XRD analysis. The morphology was determined through atomic force microscopy (AFM) imaging. The XPS survey spectra on the etched surfaces of TiN film exhibited the characteristic Ti2p, N1s, O1s peaks at the corresponding binding energies 454.5, 397.0, and 530.6 eV respectively. The characteristic Raman peaks were observed from the Laser Raman spectrometer. Platelet adhesion experiments were done to examine the interaction between blood and the materials in vitro. On Control samples (CP Ti), platelets were seen as aggregates, whereas on coated samples, platelets were seen as singles, without any significant spreading. Cytocompatibility studies of coated samples were carried out with bare titanium (CP Ti — ASTM B 348) as controls. L-929 mouse fibroblast cells were used for samples. All materials showed good cytocompatbility with cell lines used.

Evaluation of Thin Film Titanium Nitride Electrodes for Electroanalytical Applications

Abstract: Titanium nitride is a hard and inert conducting material that has yet not been widely used as electrode material for electroanalytical applications although there are highly developed protocols available to produce well adherent micro and nanostructured electrodes. In this paper the possibilities of using titanium nitride thin films for electroanalytical applications is investigated. Scanning electrochemical microscope (SECM)was used for analysis of the redox kinetics of a selected fast redox couple at thin films of titanium nitride (TiN)in different thicknesses. The investigation was carried out by approaching an amperometric ultramicroelectrode (UME)to the TiN film while the soluble redox couple (ferrocenemethanol/ferrociniummethanol)served as mediator in a SECM configuration. The substrate was biased at a potential so that it rereduces the species being produced at the UME, thus controlling the feedback effect. Normalized current – distance curves were fitted to the theoretical model in order to find the apparent heterogeneous standard rate constant (k8)at the sample. The data are further supported by structural investigation of the TiN films using scanning force microscopy and X-ray photoelectron spectroscopy. It was found that the kinetics are little influenced by prolonged storage in air. The heterogeneous standard rate constants in 2 mM ferrocenemethanol were (0.73 � 0.05) � 10 � 3 cm s � 1 for 20 nm TiN thin layer, (1.5 � 0.2) � 10 � 3 cm s � 1 for 100 nm TiN thin layer and (1.3 � 0.2) � 10 � 3 cm s � 1 for 300 nm TiN thin layer after prolonged storage in air. Oxidative surface treatment (in order to remove organic adsorbates)decreased the kinetics in agreement with a thicker oxide layer on the material. The results suggest that their direct use for amperometric detection of reversible redox systems in particular at miniaturized configurations may be advantageous.

In situ spectroscopic ellipsometry study on the growth of ultrathin TiN films by plasma-assisted atomic layer deposition

Abstract: The growth of ultrathin TiN films by plasma-assisted atomic layer deposition (PA-ALD) was studied by in situ spectroscopic ellipsometry (SE). In between the growth cycles consisting of TiCl4 precursor dosing and H2–N2 plasma exposure, ellipsometry data were acquired in the photon energy range of 0.75–5.0eV. The dielectric function of the TiN films was modeled by a Drude-Lorentz oscillator parametrization, and the film thickness and the TiN material properties, such as conduction electron density, electron mean free path, electrical resistivity, and mass density, were determined. Ex situ analysis was used to validate the results obtained by in situ SE. From the in situ spectroscopic ellipsometry data several aspects related to thin film growth by ALD were addressed. A decrease in film resistivity with deposition temperature between 100 and 400°C was attributed to the increase in electron mean free path due to a lower level of impurities incorporated into the films at higher temperatures. A change in resist...

Influence of substrate temperature on structure and mechanical, properties of multi-element (AlCrTaTiZr)N coatings

Abstract: Multi-element (AlCrTaTiZr)N coatings are prepared by reactive RF magnetron sputtering for a constant argon and nitrogen flow. The influence of the substrate temperature (100 to 500 °C) on the chemical composition, microstructure and mechanical properties of these coatings is investigated. A reduction of the nitrogen concentration is observed with increasing the substrate temperature. X-ray diffraction (XRD) shows that these coatings are of a single-phase face-centered-cubic structure. Furthermore, it is determined from XRD analysis that there is an increase in (200) peak intensity and the decrease in crystallite size and lattice parameter, for increasing substrate temperature. An increase in substrate temperature results in a monotonic decrease of compressive internal macrostress from 3.2 to 2.0 GPa. High hardness and elastic modulus around 35 and 350 GPa, respectively, were obtained nearly independent of the substrate temperature.