The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
We have investigated the plasma chemistry of process gases consisting of hydrogen with a small admixture of chlorinated methanes in a pulsed r.f. discharge. The temporal development of certain species in the plasma was explored by experiment and simulation. Experiment and simulation are in good agreement and show a very fast decomposition of the chlorinated methanes to the main stable species hydrogen...
Natural diamond irradiated by krypton ions with 210 or 247MeV energy within a dose range of 5x10 10 -1.2x10 14 cm -2 has been investigated by optical absorption, photoluminescence and electric methods. The main features of the absorption spectra of the irradiated diamond are a GR1-band and a continuous absorption band in the ultraviolet part of a spectrum. 800...
A newly developed process called time-modulated chemical vapour deposition (TMCVD) was employed to deposit smooth polycrystalline diamond films onto silicon substrates using both microwave plasma CVD (MPCVD) and hot-filament CVD (HFCVD) systems. The distinctive feature of the TMCVD process, which separates it from the conventional diamond CVD process, is that it pulses methane (CH 4 ) at different...
Diamond thin films have been synthesized by hot-filament chemical vapor deposition process using a mixture of methane and hydrogen gases. The samples were subjected to very high-energy ion irradiation (100MeV Au 7+ ions). The field emission characteristics of ion-irradiated samples have been studied. High emission currents and low turn-on and threshold fields were obtained for ion-irradiated...
In order to develop an easy and rapid elements-doped diamond film synthesis process, as a basic study, rapid diamond film deposition using combustion flame CVD and nitriding of the diamonds using supersonic expanding nitrogen plasma jets were carried out. The supersonic expanding plasma jets can be used as low-temperature plasma jets with high chemical reactivity due to supersonic adiabatic expansion...
Annealing of diamond implanted with hydrogen results in “island” graphitization and formation of bubbles (blistering). Bubbles are formed at the depth of the graphitized layer and filled with hydrogen. Based on elasticity theory, the pressure of gas and the amount of gaseous matter in the bubble as well as tensile stress in the upper part of the bubble are calculated.
Ellipsometric analysis of the buried graphitized layer formed in the He + -implanted and annealed diamond has been made. Spectroscopic ellipsometry data in the 360–1050nm range at the incident angles between 65° and 75° were fitted based on a three-layer structure model. Using optical spectroscopy, atomic force and white-light interferometry microscopy data the n and k spectra of graphitized...
X-ray synchrotron radiation is a very powerful tool in structural analysis of solids. Due to its extremely high intensity and low angular divergence, synchrotron radiation allows for the study of structures that otherwise is impossible. Here, the typical studies on different semiconductor materials using various methods of synchrotron X-ray scattering are presented.Ion implantation in compound semiconductors...
Microstructural changes and annealing/graphitization processes induced by thermal annealing in vacuum at 200–1700°C and by irradiation of a KrF excimer laser are studied in deuterium-implanted (doses 0.5–12×10 16 cm −2 ) diamond single crystals and polycrystalline CVD diamonds. The specific features of D + implanted samples—low critical doses, island-type graphitization and...
Diamond-like carbon (DLC) films made by plasma chemical vapor deposition (CVD) have many useful properties for tribological characteristics. Especially, friction coefficient is very low. However, the films have weak points i.e., very low heatproof temperature of less than 300°C and low hardness insufficient for industrial applications like machine tools. On the other hand, it is well known that diamond...
Various ion-beam etching characteristics of diamond and selectivity between diamond and spin-on-glass (SOG) were examined. The maximum selectivity of diamond and SOG was 12.7 in oxygen reactive ion-beam etching process at 100V acceleration voltage. Using this etching condition and dot-shaped SOG mask, conical diamond field electron emitter arrays with 30nm curvature radius, 2.58μm base radius and...
In hot-filament CVD the gas-phase composition is a vital parameter for diamond coating results. Concentrations of carbon-containing species have significant influence on growth rate, quality and morphology of deposited diamond. To learn more about the correlations between process parameters and gas species concentrations we applied the highly sensitive infrared tunable diode laser absorption spectroscopy...
A hot filament plant for chemical vapor deposition of crystalline diamond featuring new operating stages has been built. It allows (i) a separate methane feed locally at substrate position and (ii) supplying a forced gas flow towards the substrate. To understand the effect of these two features on diamond growth, the results of systematic diamond growth experiments are discussed. To reveal the effects...
Si 3 N 4 tools were coated with a thin diamond film using a Hot-Filament Chemical Vapour Deposition (HFCVD) reactor, in order to machining a grey cast iron. Wear behaviour of these tools in high speed machining was the main subject of this work. Turning tests were performed with a combination of cutting speeds of 500, 700 and 900mmin −1 , and feed rates of 0.1, 0.25 and 0.4mmrot...
The mould making industry is known to be worldwide in rapid expansion, due to the fact that polymeric based materials are increasingly replacing conventional used ones, thus placing enormous challenges on production methods and tools.The application of chemical vapour deposition (CVD) diamond coatings onto moulds can be a promising tool to improve properties such as adhesion, reduction on abrasion...
In order to develop wear resistance diamond/molybdenum (Mo) hybrid coating process can be conducted in open air. Diamond deposition on the molybdenum with thermal stress buffer layer coated mild steel substrate by the combustion flame chemical vapor deposition (CFCVD) was carried out. As the thermal stress buffer layer, atmospheric plasma sprayed Mo/Fe mixture coating was deposited between Mo top...
This paper reports the results of a two-step hot filament chemical vapor deposition method to improve the quality of diamond films. Diamond films were deposited on a Si(100) substrate having an area of 45cm 2 and a thickness of 60μm, employing a HFCVD system. The first step is the growth of CVD diamond in the HFCVD reactor. In the second step, the samples were treated in a saturated solution...
The hydrogenation of Ib-type single crystalline diamond with grain size of several tens of micrometers, synthesized by high-pressure and high-temperature (HPHT) sintering, was carried out by hydrogen plasma treatment in a hot-filament chemical vapor deposition (HFCVD) system. After exposure to air, the surface conductivity of (001) and (111) facets of HPHT single crystalline diamond was measured....
The control of the nucleation density is essential for the production of ultra-thin, continuous and well adhered nanocrystalline diamond coatings. Surface pre-treatments such as abrasive scratching with diamond powder or bias enhanced nucleation are commonly used methods. In this work, surface activation by a pre-growth step is done using the hot-filament chemical vapour deposition (HFCVD) technique...
The embedding of surface-modified granulates into metallic matrices is a promising way to optimize the interface matrix/granulate in respect to mechanical and thermal properties. In the case of surface modification by coating, a reliable determination of the coating thickness on granulates is desirable, since the interface properties may depend on it to a critical extent. This paper proposes a simple...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.