Hard Carbon Coatings: The Way Forward

Since the first reports by Aisenberg and Chabot in 1971 indicating the possibility of producing hard amorphous (so-called diamondlike) carbon (DLC) films, many experimental and theoretical research results have been published outlining the properties and film growth mechanisms of these films deposited by a variety of techniques. Polycrystalline and even quasimonocrystalline diamond thin films have also been produced, thus providing a wide range of wear and corrosion properties. The difference between these materials and graphite led to a prediction of rapid market growth for hard carbon. However this has not materialized. A large number of carbonbased films have been produced with differences in hardness, elasticity, friction coefficient, optical and electronic bandgap, electrical and thermal conductivity, and thermal stability. In addition these materials can show very different practical adhesion properties, which depend also on the substrate material and composition. Cost, deposition rate and temperature, geometry, and size of the coating chamber are additional variables. As a result, many of these materials can only be used for a limited range of applications. It is now possible to better understand the suitability of various coatings and the causes of the early failures that occurred through unsuitable material choices. This improved understanding should allow improvements in the performance and reliability of hard carbon films and perhaps trigger the kind of market growth that was originally foreseen but failed to materialize.

Download Full-text

Hard Carbon Films with Various Microstructure Prepared by Ion Assisted Evaporation

MRS Proceedings ◽

10.1557/proc-316-911 ◽

1993 ◽

Vol 316 ◽

Cited By ~ 1

Author(s):

J. Ullmann ◽

A. Weber ◽

U. Falke

Keyword(s):

Growth Mechanism ◽

Film Growth ◽

Carbon Films ◽

Carbon Surface ◽

Vickers Indentation ◽

Structure Modification ◽

Hard Carbon ◽

Ion Etching ◽

Ion Energy ◽

Free Ion

ABSTRACTFor a deeper understanding of the creation of carbon films the hydrogen-free ion assisted evaporation (IAE) method with neon species was used. Variation of the ion parameters energy and ion to neutral arrival ratio, delivering the necessary energy for modification of the film growth, results in different microstructures investigated with EELS, HRTEM and TED as well as different microhardnesses measured by dynamical Vickers indentation. A possible film growth mechanism is proposed based on an ion etching of mainly sp2-bonded carbon surface atoms and on defect dominated structure modification below the surface depending on the ion energy

Download Full-text

W261003 Tribological Properties of Hard Carbon films and Evaluation of Adhesion Properties

The Proceedings of Mechanical Engineering Congress Japan ◽

10.1299/jsmemecj.2014._w261003-1 ◽

2014 ◽

Vol 2014 (0) ◽

pp. _W261003-1-_W261003-4

Author(s):

Tsuguyori OHANA

Keyword(s):

Tribological Properties ◽

Carbon Films ◽

Hard Carbon ◽

Adhesion Properties

Download Full-text

Direct STEM ADF imaging of gold on silicon (111)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100154330 ◽

1989 ◽

Vol 47 ◽

pp. 472-473

Author(s):

P. Xu ◽

E. J. Kirkland ◽

J. Silcox

Keyword(s):

Film Growth ◽

Heavy Atom ◽

High Vacuum ◽

Dark Field ◽

Thin Metal Film ◽

Base Pressure ◽

Ultra High Vacuum ◽

Specimen Preparation ◽

Dark Field Imaging ◽

Wide Range

Many studies of thin metal film growth and the formation of metal-semiconductor contacts have been performed using a wide range of experimental methods. STEM annular dark field imaging could be an important complement since it may allow direct imaging of a single heavy atom on a thin silicon substrate. This would enable studies of the local atomic arrangements and defects in the initial stage of metal silicide formation.Preliminary experiments were performed in an ultra-high vacuum VG HB501A STEM with a base pressure of 1 × 10-10 mbar. An antechamber directly attached to the microscope for specimen preparation has a base pressure of 2×l0-10 mbar. A thin single crystal membrane was fabricated by anodic etching and subsequent reactive etching. The specimen was cleaned by the Shiraki method and had a very thin oxide layer left on the surface. 5 Å of gold was deposited on the specimen at room temperature from a tungsten filament coil monitored by a quartz crystal monitor.

Download Full-text

Microstructural characterization of YBaCuO Films on LaAlO3 substrates

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100152872 ◽

1989 ◽

Vol 47 ◽

pp. 180-181

Author(s):

E. L. Hall ◽

A. Mogro-Campero ◽

N. Lewis ◽

L. G. Turner

Keyword(s):

Dielectric Constant ◽

Single Crystal ◽

Film Growth ◽

Microstructural Characterization ◽

Lattice Parameter ◽

Film Plane ◽

Substrate Material ◽

High Loss ◽

Amorphous Substrates ◽

High Dielectric

There have been a large number of recent studies of the growth of Y-Ba-Cu-O thin films, and these studies have employed a variety of substrates and growth techniques. To date, the highest values of Tc and Jc have been found for films grown by sputtering or coevaporation on single-crystal SrTiO3 substrates, which produces a uniaxially-aligned film with the YBa2Cu3Ox c-axis normal to the film plane. Multilayer growth of films on the same substrate produces a triaxially-aligned film (regions of the film have their c-axis parallel to each of the three substrate <100> directions) with lower values of Jc. Growth of films on a variety of other polycrystalline or amorphous substrates produces randomly-oriented polycrystalline films with low Jc. Although single-crystal SrTiO3 thus produces the best results, this substrate material has a number of undesireable characteristics relative to electronic applications, including very high dielectric constant and a high loss tangent at microwave frequencies. Recently, Simon et al. have shown that LaAlO3 could be used as a substrate for YBaCuO film growth. This substrate is essentially a cubic perovskite with a lattice parameter of 0.3792nm (it has a slight rhombohedral distortion at room temperature) and this material exhibits much lower dielectric constant and microwave loss tangents than SrTiO3. It is also interesting from a film growth standpoint since it has a slightly smaller lattice parameter than YBa2Cu3Ox (a=0.382nm, b=c/3=0.389nm), while SrTiO3 is slightly larger (a=0.3905nm).

Download Full-text

Gluten-Free Dry Mixtures with Rice and Amaranth for Children over Three Years Old with Gluten Intolerance

Food Industry ◽

10.29141/2500-1922-2020-5-1-3 ◽

2020 ◽

Vol 5 (1) ◽

pp. 23-31

Author(s):

Sergey Urubkov ◽

Svetlana Khovanskaya ◽

Ekaterina Pyrieva ◽

Olga Georgieva ◽

Stanislav Smirnov

Keyword(s):

Celiac Disease ◽

Treatment Effectiveness ◽

Raw Materials ◽

Calculated Data ◽

Limited Range ◽

Gluten Free ◽

Fruit And Vegetable ◽

Organoleptic Evaluation ◽

Free Products ◽

Wide Range

Diet therapy is one of the main approaches to the treatment of a wide range of diseases of the digestive system. The treatment effectiveness of celiac disease depends on how strictly the patient adheres to a gluten-free diet. It is often disrupted due to the limited range of recommended foods and dishes, especially for children who are particularly sensitive to dietary restrictions. In this case, the development of new types of specialized gluten-free products is relevant, allowing to expand the diet both in terms of nutritional value and taste diversity. This study concerns the recipe developments of dry gluten-free mixtures using rice and amaranth with the inclusion of fruit and vegetable and berry raw materials intended for the nutrition of children over three years old suffering from celiac disease. When developing the recipes, researchers used various combinations of rice and amaranth flour, as well as fruit and vegetable powders. The rice flour composition varied in the range from 15 to 75%; amaranth – from 15 to 45%; fruit and vegetable and berry powders – up to 10%. The finished product was gluten-free cookies, muffins, pancakes made of rice and amaranth. Organoleptic evaluation showed that the studied samples of gluten-free cookies have high quality characteristics, have a pleasant taste and aroma. According to the calculated data, specialized gluten-free dry mixtures intended for children over three years with celiac disease can serve as an important source of: vegetable carbohydrates – from 26.81 to 55.19 g / 100g of finished products; protein – from 4.06 to 11.82 g/100g of finished products; dietary fiber – from 3.82 to 6.36 g/100g of finished products; and energy – from 158.12 to 333.96 kcal/100g of finished products) The developed recipess of gluten-free products can help to provide children with an adequate amount of nutrients and energy.

Download Full-text

Using Molecular-Beam Mass Spectrometry to Study the Pecvd of Diamondlike Carbon Films

MRS Proceedings ◽

10.1557/proc-334-129 ◽

1993 ◽

Vol 334 ◽

Cited By ~ 1

Author(s):

I.B. Graff ◽

R.A. Pugliese ◽

P.R. Westmoreland

Keyword(s):

Mass Spectrometry ◽

Vapor Deposition ◽

Molecular Beam ◽

Film Growth ◽

Chemical Vapor ◽

Carbon Films ◽

Total Flow ◽

Measured Concentration ◽

Molecular Beam Mass Spectrometry ◽

Diamondlike Carbon

AbstractMolecular-beam mass spectrometry has been used to study plasma-enhanced chemical vapor deposition (PECVD) of diamondlike carbon films. A threshold-ionization technique was used to identify and quantify species in the plasma. Mole fractions of H, H2, CH4, C2H2, C2H6 and Ar were measured in an 83.3% CH4/Ar mixture at a pressure of 0.1 torr and a total flow of 30 sccm. Comparisons were made between mole fractions measured at plasma powers of 25W and 50W. These results were compared to measured concentration profiles and to film growth rates.

Download Full-text

Influence of Substrate Materials on Nucleation and Properties of Iridium Thin Films Grown by ALD

Coatings ◽

10.3390/coatings11020173 ◽

2021 ◽

Vol 11 (2) ◽

pp. 173

Author(s):

Paul Schmitt ◽

Vivek Beladiya ◽

Nadja Felde ◽

Pallabi Paul ◽

Felix Otto ◽

...

Keyword(s):

Thin Films ◽

Film Growth ◽

Bulk Material ◽

Atomic Layer ◽

Substrate Material ◽

Fused Silica ◽

Silicon Wafers ◽

Force Microscopy ◽

Angle Measurements ◽

Influence Of Substrate

Ultra-thin metallic films are widely applied in optics and microelectronics. However, their properties differ significantly from the bulk material and depend on the substrate material. The nucleation, film growth, and layer properties of atomic layer deposited (ALD) iridium thin films are evaluated on silicon wafers, BK7, fused silica, SiO2, TiO2, Ta2O5, Al2O3, HfO2, Ru, Cr, Mo, and graphite to understand the influence of various substrate materials. This comprehensive study was carried out using scanning electron and atomic force microscopy, X-ray reflectivity and diffraction, four-point probe resistivity and contact angle measurements, tape tests, and Auger electron spectroscopy. Within few ALD cycles, iridium islands occur on all substrates. Nevertheless, their size, shape, and distribution depend on the substrate. Ultra-thin (almost) closed Ir layers grow on a Ta2O5 seed layer after 100 cycles corresponding to about 5 nm film thickness. In contrast, the growth on Al2O3 and HfO2 is strongly inhibited. The iridium growth on silicon wafers is overall linear. On BK7, fused silica, SiO2, TiO2, Ta2O5, Ru, Cr, and graphite, three different growth regimes are distinguishable. The surface free energy of the substrates correlates with their iridium nucleation delay. Our work, therefore, demonstrates that substrates can significantly tailor the properties of ultra-thin films.

Download Full-text

Characterization and Performance of Carbon Films Deposited by Plasma and Ion Beam Based Techniques

MRS Proceedings ◽

10.1557/proc-354-87 ◽

1994 ◽

Vol 354 ◽

Cited By ~ 7

Author(s):

K.C. Walter ◽

H. Kung ◽

T. Levine ◽

J.T. Tesmer ◽

P. Kodali ◽

...

Keyword(s):

Wear Rate ◽

Surface Area ◽

Ion Beam ◽

Carbon Films ◽

The Self ◽

Line Of Sight ◽

Rf Power ◽

Hard Carbon ◽

Self Bias ◽

Cathodic Arc

AbstractPlasma and ion beam based techniques have been used to deposit carbon-based films. The ion beam based method, a cathodic arc process, used a magnetically mass analyzed beam and is inherently a line-of-sight process. Two hydrocarbon plasma-based, non-line-of-sight techniques were also used and have the advantage of being capable of coating complicated geometries. The self-bias technique can produce hard carbon films, but is dependent on rf power and the surface area of the target. The pulsed-bias technique can also produce hard carbon films but has the additional advantage of being independent of rf power and target surface area. Tribological results indicated the coefficient of friction is nearly the same for carbon films from each deposition process, but the wear rate of the cathodic arc film was five times less than for the self-bias or pulsed-bias films. Although the cathodic arc film was the hardest, contained the highest fraction of sp3 bonds and exhibited the lowest wear rate, the cathodic arc film also produced the highest wear on the 440C stainless steel counterface during tribological testing. Thus, for tribological applications requiring low wear rates for both counterfaces, coating one surface with a very hard, wear resistant film may detrimentally affect the tribological behavior of the counterface.

Download Full-text