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[en] In order to find out the reaction processes and a series of morphology for the titanium nitride powders obtained from the vapor phase reaction of TiCl4 and NH3, experiments have been carried out in the temperature range between 200 deg C and 1200 deg C and under the pressure of atmosphere and 4.9 KPa. The reaction products and thermally decomposed powders obtained at various temperatures under the pressure of atmosphere and 4.9 KPa have been investigated by means of X-ray diffraction, TGA and electron microscopy. In the vapor phase reaction, TiNCl started forming at about 350 deg C, and TiN did at about 500 deg C. On the other hand, in the thermal decomposition reaction of the products obtained at about 200 deg C, TiN started forming at about 450 deg C either under the ammonia or the argon gas flow. Under atmospheric pressure the titanium powder of approximate particle size 0.05 μm was obtained at 1200 deg C from the vapor phase reaction, whereas 0.02 μm or less titanium nitride powder was obtained at the same temperature under the pressure of 4.9 KPa. (Author)
[en] Highlights: • The interfacial dislocations by GMS and O-lattice are calculated. • Interpretation of interfacial dislocations in Ni–TiN system is given. • Secondary Burgers vectors of interfacial dislocations is obtained. • Occurrence frequency of precipitates is interpreted by O-line model. The preferred state in an interface is the key to evaluating misfit strain, especially for the interphase interfaces in secondary preferred state. The structure of good matching site (GMS) in a GMS clusters offers a guidance for the preferred state, especially for identifying the coincidence site lattice in two dimension for secondary preferred state and the Burgers vectors in a large misfit system. Here, we combine the GMS with O-lattice theory to calculate the secondary dislocation structure in the habit planes of the type II and III TiN precipitates in a Ni–TiN system. We find that under a slight elastic strain, the type III habit plane contains a single set of secondary dislocations, consistent with the experimental observation. The type II habit plane contains three sets of secondary dislocations, two of which can be relaxed to be nearly parallel and another of which may be invisible in diffraction contrast due to its short Burgers vector. The present study provides a reasonable interpretation to the observed interfacial dislocations, and also suggests Burgers vectors for the dislocations that are not determined experimentally.
[en] An atomization gas used in arc spraying has a great influence on the nitriding process of titanium. Hence, we investigated the chemical composition of titanium coatings reflecting the nitriding process with the use of air, N2 and Ar as the atomization gas. The ratios of contents (at.%) for nitrogen and oxygen in the coatings were 3:1 (air), 6:1 (N2) and 2:1 (Ar), and the oxygen contents were almost the same. The peak height ratios of TiN0.3 to TiN in XRD rose with decrease of the nitrogen content. The TiN peaks of all of the coatings were slightly shifted to higher angles by the oxygen, and their intensity was influenced only by the nitrogen content. In addition, β-Ti and Fe2Ti were detected in XRD from the surface of thin coatings, and an alloyed layer in the interface region between coating and substrate was observed in SEM. The Ar atomized coating had the thickest alloyed layer. N2 atomization is efficient in the TiN formation. Ar atomization restrains the reaction of titanium with the nitrogen and oxygen, and promotes the chemical bonding between the coating and substrate
[en] This paper studies the effects of both the positive and negative forming processes on the resistive switching characteristics of a Pt/Yb2O3/TiN RRAM device. The polarity of the forming process can determine the transition mechanism, either bipolar or unipolar. Bipolar behavior exists after the positive forming process, while unipolar behavior exists after the negative forming process. Furthermore, the bipolar switching characteristics of the Pt/Yb2O3/TiN device can be affected by using a reverse polarity forming treatment, which not only reduces the set and reset voltage, but also improves the on/off ratio.
[en] We have investigated the influence of N2 plasma treatment on the selective deposition of copper (Cu) on the titanium nitride (TiN) part of a substrate consisting of TiN and borophosphosilicate glass (BPSG). It is found that N2 plasma treatment under optimum conditions improves the selective Cu deposition and the physical properties of the deposited Cu films. These improvements are explained by a reduction of hydroxyl radicals at the BPSG surface and an increase in the free energy barrier of TiN, as well as that of the BPSG substrate. Furthermore, Rutherford backscattering spectrometry measurements reveal that N2 plasma treatment improves the function of the TiN layer as a barrier against Cu diffusion through enhanced stuffing of the TiN
[en] This paper studies the effect of doping on BON-based resistive switching characteristics. Typical bipolar resistive switching behavior can be observed in Pt/BON/TiN and Pt/BON:Gd/TiN devices. The conductive path(s) of the Pt/BON/TiN is vacancy-dominated while the Pt/BON:Gd/TiN is metal-dominated. Additionally, there is an atypical bipolar resistive switching in the Gd-doping device. This atypical characteristic has not only a size effect, but also a lower operating current. The resistance transitions are due to the variation in conductance of the switching layer, which is clearly influenced by the different area size. A mechanism is proposed to explain this atypical characteristic. - Highlights: ► The boron oxynitride thin film with and without Gd doping were fabricated. ► Doping Gd metal exhibits filament and interface type resistance switching behavior. ► A mechanism can be proposed to illustrate the doping metal effect
[en] We present the effects of both deposition temperature and deposition time on the surface characteristics of TiN-coated high-speed steel(AISI M2) by arc ion plating. The microparticles, surface roughness, microhardness, coated layer thickness, adhesion strength, and atomic distribution of Ti, N, and Fe elements were measured for various deposition temperatures and times. The results demonstrated that a deposition temperature in the range of 400 to 500 .deg. C had a slight influence on the surface characteristics, while a deposition time in the range of 10 to 180 min had a great influence on the microparticles, surface roughness, microhardness, coated thickness, atomic distribution of Ti, and adhesion strength
[en] The introduction of two-grid inside a conventional process system produces a reactive coating deposition and increases metal ion ratio in the plasma, resulting in denser and smoother films. The corrosion behaviors of TiN coatings were investigated by electrochemical methods, such as potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS) in deaerated 3.5% NaCl solution. Electrochemical tests were used to evaluate the effect of microstructure on the corrosion behavior of TiN coatings exposed to a corrosive environment. The crystal structure of the coatings was examined by X-ray diffractometry (XRD) and the microstructure of the coatings was investigated by scanning electron microscopy (SEM) and transmission electron spectroscopy (TEM). In the potentiodynamic polarization test and EIS measurement, the corrosion current density of TiN deposited by two grid-attached magnetron sputtering was lower than TiN deposited by conventional magnetron type and also presented higher Rct values during 240 h immersion time. It is attributed to the formation of a dense microstructure, which promotes the compactness of coatings and yields lower porosity
[en] Two contact systems on AlGaN/GaN-heterostructures were investigated with respect to their electrical performance and surface morphology. The first system is a standard Ti/Al-based multilayer contact system, generally exhibiting an excellent electrical performance. However strong surface roughening and degradation after annealing due to high diffusion rates of aluminum and gold often occur, which in turn affect the contact stability and reliability. Thus, a contact system based on sputtered titanium nitride was studied. TiN is well known as a thermally stable material with a good conductivity, but is used only indirectly via thermal transformation of thin Ti layers in typical group III nitride circuits. Using the TiN contact system, we were able to achieve a competitive electrical performance with a minimum value of contact resistivity of 1.8 × 10−5 Ω cm2 at an annealing temperature of 850 °C for 45 s. Most importantly, the surface roughness was greatly reduced (maximum rms values of 1.8 nm). The contact formation via rapid thermal processing was studied using Auger electron depth profiling. (paper)