Nitrides silicon nitride

CVD plays an increasingly important part in the design and processing of advanced electronic conductors and insulators as well as related structures, such as diffusion barriers and high thermal-conductivity substrates (heat-sinks). In these areas, materials such as titanium nitride, silicon nitride, silicon oxide, diamond, and aluminum nitride are of particular importance. These compounds are all produced by CVD. 1 1 PI... 

Refractories such as boron nitride, silicon nitride, silicon carbide, and boron carbide are of great importance for the production or protection of systems which can be operated in very high... 

Silicon Nitride. Silicon nitride is manufactured either as a powder as a precursor for the production of hot-pressed parts or as self-bonded, reaction-sintered, silicon nitnde parts. 

Silicon Nitride. Silicon nitride produced by high-temperature (>700 °C) CVD is a dense, stable, adherent dielectric that is useful as a passivation or protective coating, interlevel metal dielectric layer, and antireflection coating in solar cells and photodetectors. However, these applications often demand low deposition temperatures (<400 °C) so that low-melting-point substrates or films (e.g., Al or polymers) can be coated. Therefore, considerable effort has been expended to form high-quality silicon nitride films by PECVD. 

Silicon Nitride Silicon nitride is a synthetic raw material which is synthesized by various hig -temperature reactions between 1000... 

For related information, see the discussions of boron nitride, silicon nitride and ceramic coatings in Section 27.6. 

EINECS 234-796-8 Roydazide Silicon nitride Silicon nitride (Si3N4). A proprietary trade name for silicon nitride used for the manufacture of turbine blades and generally where a temperature of up to 1650°C is required. Two crystalline forms, a and fi mp = 1900° d = 3.2. Doulton. 

Unlike the interstitial nitrides, the covalent nitrides are not metallic compounds. The differences in electronegativity and atomic size between the nitrogen and the other element are small and their electronic bonding is essentially covalent. In this respect, they are similar to the covalent carbides. They include the nitrides of Group mb (B, Al, Ga, In, Tl) and those of silicon and phosphorus. Of these, only three are considered refractory boron nitride, silicon nitride, and aluminum nitride. These are reviewed in Chs. 12 and 13. 

The five covalent refractory carbides and nitrides, silicon carbide, boron carbide, aluminum nitride, silicon nitride, and boron nitride are all produced on an industrial scale and all have a number of successfiil large-volume applications. Of these five, the latecomer silicon nitride, either in bulk/monolithic form or as a coating, may have the most promising future. 

Four materials play an increasingly important part in the design of advanced electronic and optical products titanium nitride, silicon nitride, aluminum nitride, and silicon carbide. These materials have contributed to a sizeable extent to the dramatic progress of the semiconductor and optical industries in the last few years. The major applications are as follows. 

In order to achieve high thermal conductance, aluminum nitride, silicon nitride, silicon carbide and the like which have high thermal conductance are being tried as ceramic ingredients. However whatever the type, it is difficult to exceed that of the alumina used in HTCCs. However, compared with resin materials, glass/alumina composites can achieve thermal conductivity more than ten times higher. 

Singh, M., Martinez Fernandez, J., Asthana, R., Rico, J. R. (2012). Interfacial characterization of silicon nitride/silicon nitride joints brazed using Cu-base active metal interlayers. Ceramics International, 38, 2793-2802. doi 10.1016/j. ceramint.2011.11.050. 

As noted, the oxidation resistance of silicon nitride ceramics depends on the type and concentration of the sintering aids. In materials designed for high temperature appHcations the specific weight gain resulting from oxidation upon a 500-h air exposure at 1200°C and 1350°C is about 1—2 g/m and 2—4 g/m, respectively. The kinetics of the oxidation process have been iavestigated (63,64) as has the corrosion resistance (65). Corrosion resistance is also dependent on material formulation and density. 

Silicon Nitride. SiUcon nitride is manufactured either as a powder as a precursor for the production of hot-pressed parts or as self-bonded, reaction-sintered, siUcon nitride parts. a-SiUcon nitride, used in the manufacture of Si N intended for hot pressing, can be obtained by nitriding Si powder in an atmosphere of H2, N2, and NH. Reaction conditions, eg, temperature, time, and atmosphere, have to be controlled closely. Special additions, such as Fe202 to the precursor material, act as catalysts for the formation of predorninately a-Si N. SiUcon nitride is ball-milled to a very fine powder and is purified by acid leaching. SiUcon nitride can be hot pressed to full density by adding 1—5% MgO. 

Fig. 12. (a) A cross section of multiple coatings of TiN on TiC on a silicon nitride-based tool material (b) multicoatings on a SiAlON-based tool material. 

Creep Resistsince. Studies on creep resistance of particulate reinforced composites seem to indicate that such composites are less creep resistant than are monolithic matrices. Silicon nitride reinforced with 40 vol % TiN has been found to have a higher creep rate and a reduced creep strength compared to that of unreinforced silicon nitride. Further reduction in properties have been observed with an increase in the volume fraction of particles and a decrease in the particle size (20). Similar results have been found for SiC particulate reinforced silicon nitride (64). Poor creep behavior has been attributed to the presence of glassy phases in the composite, and removal of these from the microstmcture may improve the high temperature mechanical properties (64). 

This mixture of gases has been used to prepare silicon nitride particles photochemically, the overall reaction being represented by... 

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