Showing papers on "Nitride published in 1971"

Characterization of Silicon Nitride Films

Abstract: Various "silicon nitride" films have been prepared from , N2, , and in an rf‐promoted glow discharge reaction. These films are described primarily through the use of infrared absorption. Aided by ultraviolet absorption, the inclusion of excess silicon or of oxygen in the films is readily followed. Changes in index of refraction, etch rates in HF acid, and electrical conductivity of the films are correlated with the optical absorption study. Comparisons of these films with those formed by pyrolysis or by reactive sputtering are made. Some reproducible physical properties of an amorphous film are stated.

Cubic boron nitride/sintered carbide abrasive bodies

Abstract: Abrasive bodies comprising combinations of cubic boron nitride crystals and sintered carbide are disclosed. These composite bodies are prepared by superpressure processes. Cubic boron nitride contents of up to about 99 volume percent have been successfully employed in certain constructions. Similar abrasive bodies have been prepared from mixtures of cubic boron nitride, diamond and carbide powder.

Structure of Tantalum Nitrides

Abstract: The crystal structure of tantalum nitrides is examined by X-ray and electron diffraction techniques and the following seven phases are identified: TaN~0.05 (cubic, β-phase), Ta2N (hexagonal, γ-phase), δ-TaN (hexagonal), e-TaN (hexagonal), Ta5N6 (hexagonal), Ta4N5 (tetragonal) and Ta3N5 (tetragonal or monoclinic). Thin films of Ta nitrides for electron diffraction study were prepared by nitriding thin evaporated films of tantalum in ammonia and nitrogen. By heating thin films of Ta3N5 in vacuum, the phase transformations occur successively as follows: Ta3N5→Ta4N5→Ta5N6→e-TaN→Ta2N. The stucture of each nitride form is discussed.

Abrasive bodies of finely-divided cubic boron nitride crystals

Abstract: ALUMINUM ALLOYS OF NICKEL, COBALT, MANGANESE, IRON, VANADIUM AND CHROMIUM HAVE BEEN FOUND TO PROVIDE SUCCESSFUL BONDING MECHANISMS FOR THE PREPARATION OF CUBIC BORON NITRIDE (CBN) COMPACTS. THESE BONDING MEDIA ARE PARTICULARLY EFFECTIVE FOR PREPARING COMPACTS OF CBN CRYSTALS SMALLER THAN ABOUT 30 MICROMETERS IN LARGEST DIMENSION. THE PREPARATION OF TOOL INSERTS MADE OF CUBICBORON NITRIDE CRYSTALS BONDED TO AND SUPPORTED ON A SINTERED CARBIDE MASS IS DESCRIBED WHEREIN SUCH AN ALUMINUM ALLOY IS USED AS THE BONDING MEDIUM.

Microstructural studies on silicon nitride

Abstract: Thin specimens of reaction sintered and hot pressed silicon nitride have been prepared by ion beam thinning and examined in the Harwell million volt microscope. It has been found that reaction sintered material consists of large grains, which are mostlyβ-Si3N4, in a fine grained matrix ofα-Si3N4. Fibres are frequently observed within the pores, the type of fibre depending on the size of the pore. The hot pressed material consists largely of two types of grain, small angular grains ofβ-Si3N4 and larger irregular grains. There is also some non-crystalline material between the angular grains and there are numerous small unidentified inclusions. The grains ofβ-Si3N4 generally contain dislocations and examination of these shows that most have a 〈0001〉 Burgers vector. The remaining dislocations appear to be more complex, frequently occurring as multiple images, and have not been unambiguously identified. An analysis of dislocations inβ-Si3N4 shows that 〈0001〉 dislocations are the most stable and are also likely to be most mobile with {10¯10} as the primary slip plane.

Gallium Nitride Films

Abstract: The thermal decomposition of a gallium tribromide‐ammonia complex in an ammonia, argon, or nitrogen atmosphere has been used for the deposition of gallium nitride films on silicon and hexagonal silicon carbide substrates in a gas flow system. The substrate temperature and the nature of the ambient are the most important parameters of the deposition process. Adherent and transparent films of gallium nitride have been deposited at substrate temperatures up to about 600°C in an ammonia atmosphere and up to about 750°C in a nitrogen or argon ambient. At higher temperatures, the deposit became contaminated with gallium. The gallium nitride films deposited on {111} oriented silicon substrates at 600°–700°C were found to show a (110) fiber orientation. Epitaxial, single crystalline gallium nitride films have been grown successfully on the basal plane of hexagonal silicon carbide substrates at 520°–600°C. These films are of high resistivity indicating that the thermal decomposition of gallium nitride is negligible. Thus, the thermal decomposition of the gallium tribromide‐ammonia complex provides a new promising technique for the crystal growth of gallium nitride.

Chemical vapor deposition coatings on titanium

Abstract: A process for coating titanium-containing substrates with a dense, adherent, chemically vapor deposited coating by initially effecting a pro-tective, adhesion-promoting, intermediate layer on the titanium surface and subsequently depositing from the vapor phase a metal nitride, carbide, or carbonitride coating on the intermediate film. For example, a titanium article may be initially nitrided to provide a titanium nitride protective layer and titanium nitride, titanium carbide, or titanium carbonitride may subsequently be deposited from the vapor phase onto this film to provide a dense, adherent, protective coating on the titanium article. The barrier layer serves to pro-mote adhesion between the titanium substrate and the final overlay and to prevent reaction between the substrate and such a reaction ingredient as titanium tetrachloride, which is a preferred constituent for supplying titanium in the titanium carbide, nitride, or carbonitride final coating.

Mass of polycrystalline cubic system boron nitride and composites of polycrystalline cubic system boron nitride and other hard materials, and processes for manufacturing the same

Abstract: This invention gives bonded or compact bodies of polycrystalline cubic system boron nitride and substantially uniform composites of polycrystalline cubic system boron nitride and other hard materials, for example, metal borides, such as titanium boride and zirconium boride, covalent or metallic cabides, such as boron carbide, silicon carbide, titanium, carbide, tungsten carbide and chromium carbide, metal nitrides, such as titanium nitride, tantalum nitride, silicon nitride and aluminum nitride, metal oxides, such as alumina and silica, complex oxide such as garnet and agate, and diamond. Further, this invention provides a process of obtaining the bonded body of these materials which comprises subjecting hexagonal system boron nitride powder, or a mixture of hexagonal system boron nitride powder and cubic system boron nitride crystal powder or powders of the above-mentioned hard materials to high temperatures and high pressures.

Heat resistant and strengthened composite materials and method for producing same

Abstract: Heat resistant and strengthened composite materials are obtained by mixing, and sintering in a non-oxidizing atmosphere, the combination of powders of aluminum nitride and/or silicon nitride, with powders of an oxide of lanthanum, cerium, scandium, yttrium, and/or yttrium aluminum garnet, and with powders or whiskers of silicon carbide, boron nitride and/or carbon. The composite material so produced is characterized by high shock resistance and excellent mechanical strength.

III–V Semiconducting Compounds

Abstract: Composite Table.- Aluminum Antimonide.- Aluminum Arsenide.- Aluminum Nitride.- Aluminum Phosphide.- Boron Arsenide.- Boron Nitride.- Boron Phosphide.- Gallium Antimonide.- Gallium Arsenide.- Gallium Nitride.- Gallium Phosphide.- Indium Antimonide.- Indium Arsenide.- Indium Bismuth.- Indium Nitride.- Indium Phosphide.

Conversion of silicon nitride into silicon dioxide through the influence of oxygen

Abstract: When thin films of silicon nitride are annealed in the presence of oxygen, thin films of silicon dioxide are formed on the nitride layers while silicon nitride is consumed. The thickness of the oxide layers which are built up by reaction with dry oxygen, wet oxygen and by a mixture of oxygen and nitrogen in the presence of phosphorus pentoxide, are given as a function of time and temperature. The results are compared with the thermal oxidation of silicon.

New phases of niobium nitride

Abstract: Two new phases of niobium nitride, Nb4N5 and Nb5gN6, were identified on thin films by electron diffraction. The specimens were prepared by nitriding the evaporated thin films of niobium in ammonia. The structures of these two nitrides are isomorphous with those of Ta4N5 and Ta5N6, respectively. The Nb4N5 phase belongs to the tetragonal system with lattice parameters, a = 6.87 3 A and c = 4.29 8 A , while the Nb5N6 phase is based on the hexagonal structure having lattice parameters, a = 5.19 3 A and c = 10.38 0 A . By heating Nb5N6 in vacuum at high temperature, successive phase changes were observed: Nb5N6→δ′-NbN→δ-NbN→Nb4N3→Nb2N.

First Nitride (CrN) in Iron Meteorites

Abstract: TWO nitrides have been reported previously in stony meteorites; TiN, osbornite1, in enstatite achondrites and Si2N2O, sinoite2, in enstatite chondrites. This communication reports the first nitride, chromium nitride, to be found in iron meteorites; we made the discovery independently of each other. The mineral and its name, carlsbergite, have been approved by the Commission on New Minerals.

Method of making resistor thin films by reactive sputtering from a composite source

Abstract: A method of making high resistivity thin film resistors by reactively sputtering a composite source onto a substrate is described. The composite source comprises a first material selected from the group consisting of chromium, silicon, beryllium, aluminum and magnesium and a second material selected from the group consisting of molybdenum, tantalum, tungsten, gold, silver, platinum, osmium and iridium. In the presence of a reactive gas such as nitrogen, the first materials form a high resistivity nitride on the substrate and the second materials either form a low resistivity nitride on the substrate or are non-reactive with the nitrogen and remain in their elemental states. The resulting thin films have resistivities ranging between the high resistivity nitrides and the low resistivity nitrides depending upon the composition of the composite source.

Silicon nitride products

Abstract: A method of manufacturing silicon nitride products is of the kind in which silicon nitride powder is pressed at an elevated temperature to form the product, the pressing being continued until the product is fully densified. The method is characterised in that the fully densified product is then heated further at a temperature sufficient to convert alpha -phase silicon nitride to beta -phase silicon nitride.

Silicon nitride ceramic composites with high toughness.

Abstract: THE brittleness of ceramic materials, compared with metals, limits their use in engineering, in spite of such attractive properties as high temperature strength and oxidation resistance. Possible solutions to the brittleness problem therefore continue to be of interest. One approach advocated1 for silicon nitride has been that of fibre reinforcement, practical feasibility of which has been demonstrated2. In the carbon/silica system Crivelli-Visconti3 and Cooper have shown that high work of fracture can be obtained : we present here mechanical property data for silicon nitride/silicon carbide fibre composite materials. The potential of silicon nitride ceramics as engineering materials has been described elsewhere4.

About Nitrides and Carbonitrides and Nitride-Based Cemented Hard Alloys

Abstract: Up till now nitrides of the transition metals have attained only cursory interest as compared with the hard and refractory carbides (1,2). Practical application of nitrides has been limited to the formation of hard and wear resistant surface layers in the nitriding of steels and other iron alloys. The relatively stable nitrides of the group IV of the periodic table (TiN, ZrN, HfN) have been used as refractory materials for the manufacture of crucibles with fair thermal shock resistance, but no larger technical success followed (3). Attempts to cement nitrides with binder-metals to form hard alloys have been up to now only partly successful (4–12). Niobium nitride has gained some reputation as superconducting material with high transition temperature and uranium carbonitride seems to be of interest as promising nuclear fuel because of its stability against graphite and greater chemical stability against humidity as compared with the uranium carbides UC and UC2.

Sintering of UN as a Function of Temperature and N2 Pressure

Abstract: The sintering of uranium mononitride (UN) depends on temperature and the N2 pressure maintained over the nitride during heat treatment. At a given temperature, an N2 pressure that maintained the UN in the single-phase region slightly above the phase boundary where the reaction UN→U+½N2(g) occurred was most effective in accelerating the sintering of single-phase UN. For example, specimens sintered at 1600°C under N2 pressures of either 1140 or 1.7XlO−4 torr had essentially identical compositions, but the density of the former was 10.78 g/cm3 (75% of theoretical), whereas that of the latter was 12.20 g/cm3 (85% of theoretical). Results were similar at temperatures up to 2100°C. The X-ray lattice constant of UN sintered at reduced N2 pressures was slightly larger than that of UN sintered in 1140 torr of N2. The observed constants ranged from 4.88904 to 4.88991 A; the combined O+C content varied from 400 to 900 ppm.

Evaporation characteristics of materials from an electron beam gun II

Abstract: Measurements have been made of the evaporation characteristics of aluminum, alumina, aluminum nitride, barium titanate, boron carbide, boron nitride, carbon, copper, chromium, gold, iron, inconel, lead, magnesium, magnesium fluoride, molybdenum, nickel, niobium, permalloy, sapphire, silicon, silicon monoxide, silicon dioxide, silver, tantalum, tin, tin oxide, titanium, titanium monoxide, titanium dioxide, tungsten, and zinc. Using a 6-kW, 180 ° bent-beam gun, the deposition rate, required beam power, charge material form, and suitability for evaporation were determined for each material. The evaporation rate is reported in angstroms/minute. Methods of transferring these data to other guns are developed. The beam power limit is discussed and methods of increasing the evaporation rate of power limited materials are explored. Extension of these results to other materials is discussed and examples are given.

Compensation of radiation effects by charge transport in metal-nitride/ oxide/semiconductor structures.

Abstract: We consider the effects of ionizing radiation on complementary metal‐nitride‐oxide‐silicon (CMNOS) structures for oxide thicknesses in the range 20–50 A. The bidirectional radiation‐induced threshold‐voltage shifts in CMNOS structures are interpreted in terms of charge accumulation at the nitride‐oxide interface. The electronic recovery of preirradiation threshold‐voltage levels by carrier transport through the thin oxide is shown experimentally.

The Selective Epitaxial Growth of Silicon by Using Silicon Nitride Film as a Mask

Abstract: The selective epitaxial growth of Si through the window in silicon nitride film is studied for the SiCl4-H2 system. Experiments prove that the silicon nitride film is extremely stable compared with the usual silicon dioxide film. To find out the necessary conditions for the selective epitaxial growth, the growth rates of Si on silicon nitride film and on silicon bare surface are obtained independently from the experiment. The critical SiCl4 pressure for the nucleation on silicon nitride film is determined as a function of growth temperature. The experimental results are explained by the nucleation theory.

Relationship between Structure and Sputtering Parameters in NbN Films

Abstract: The structure of thin films of niobium nitrides was examined by reflection electron diffraction techniques. The nitride films were obtained by reactive rf sputtering of the niobium at different power levels and partial pressures of nitrogen. The films were deposited on oriented sapphire substrates maintained either at room temperature of at 400 °C. Crystal structures of three distinct phases were observed and identified as (1) α-bcc niobium with nitrogen in solid solution, (2) β-hexagonal Nb2N, and (3) δ-fcc NbN. In this study, the γ–Nb4N3 composition could not be obtained as a single phase but was always found to occur as a mixture with the δ phase. The films prepared at both high partial pressures of nitrogen and rf powers had strong textures that were dependent also on the film thickness. The electron-diffraction data showed that niobium nitride films with successive structure transformations similar to that in the bulk state can be realized and that the transformations can be correlated to the sputter...

Method of producing cubic boron nitride with aluminum containing catalyst

Abstract: An improved method for converting boron nitride from the hexagonal to the cubic form in which powdered hexagonal boron nitride is mixed with at least one catalyst selected from the group consisting of elemental aluminum, and beta -phase alloys of nickel and aluminum, and particularly NiAl, CoAl, FeNiAl, CoNiAl, CoCuAl, CuNiAl, FeNiCoAl, CuCoNiAl, and FeCoCuAl, and the mixture compressed at a pressure of from about 60 kilobars to about 85 kilobars and higher while heating to a temperature of from about 800 DEG C to about 1600 DEG C.

Vapour-phase crystallization and some physical properties of titanium nitride

Abstract: One possible method by which titanium, nitride layers may be obtained is by vapour-phase deposition using chemical transport reactions. The TiN layers in the present work were obtained from the reaction of a titanium tetrachloride, hydrogen, nitrogen mixture above 700 °K. The microhardness and reflection coefficient of the layers obtained have been investigated, in addition to the ratio of carrier concentration to effective mass. The dielectric constant and the relaxation time have been determined from the theoretical analysis of the reflection curve.

Crystal structure of an iridium complex containing a triply bridging nitride ligand

Abstract: The complex ion [Ir3N(SO4)6(H2O)3]4– has been shown by X-ray analysis of its ammonium salt to contain a coplanar Ir3N unit with an Ir–N distance of 1·918 A.

Method for forming a soft nitride layer in a metal surface

Abstract: Improved processes for nitriding and carbonitriding steel alloys by the use of gas mixtures containing a small amount of air or oxygen In the case of nitriding, a metal specimen is held in an atmosphere of ammonia gas to which is added 05 to 5 percent air by volume or 01 to 1 percent oxygen by volume at temperatures between 450* and 650*C As a result of the treatment, a soft nitride layer is formed in the surface of the specimen When carbonitriding is performed, a gas mixture containing 30 percent ammonia gas, 30 percent carbon monoxide, 5 to 10 percent air or 1 to 2 percent oxygen and the remaining volume percentage nitrogen, is employed In this case, also a soft nitride layer substantially free from Fe2N is formed in the metal surface According to this invention, the time required to perform a desired nitriding or carbonitriding is greatly reduced, while the wear resistance, fatigue resistance and toughness of the metal are highly improved