Doping silicon carbide

Carbon-doped silicon carbide, 22 535 Carbon electrodes, 12 305, 752-758 furnaces using, 12 753 grades of, 72 754 in open-arc furnaces, 72 301 production of, 72 755 properties of, 72 755-756 Carbon elimination, in steelmaking, 23 258 Carbon fiber, 77 214-215 Carbon fiber ceramic-matrix composites, 26 773... 

Chemical and phase purity are not always desirable. For example, H- and N-doped silicon carbide films behave as high temperature semiconductors, while silicon carbonitride glasses offer properties akin to glassy carbon with room temperature conductivities of 103 2 cm-118. Additional reasons for targeting materials that are not chemically or phase pure stem from the desire to control microstructural properties. 

Schnabel, C., Womer, M., Gonzalez, B., Del Olmo, I. and Braun, A.M., (2001) Photoelectrochem-ical characterization of p- and n-doped single crystalline silicon carbide and photoinduced reductive dehalogenation of organic pollutants at p-doped silicon carbide. Electrochim. Acta... 

P. H. Cuong, B. Christophe, D. Thierry, E. Babrielle, E. Claude, and J. L. Marc, High surface area silicon carbide doped with zirconium for use as catalyst support preparation, characterization and catalytic application, Appl. Catal. A 180, 385—397 (1999). 

An important application of polydimethylsilane is as a source of silicon carbide (SiC) fibres, which are manufactured under the trade-name Nicalon by Nippon Carbon in Japan. Heating in an autoclave under pressure converts polydimethylsilane to spinnable polycarbosilane (-Me2Si-CH2-) with elimination of methane. The spun fibres are then subjected to temperatures of 1200-1400 °C to produce silicon carbide fibres with very high tensile strengths and elastic moduli." As a result of their conductivity, polysilanes have also been used as hole transport layers in electroluminescent devices. In addition, the photoconductivity of polymethylphenylsilane doped with Cgo has been found to be particularly impressive. ... 

Resistivity measurements of doped, alpha-silicon carbide single crystals from —195 to 725°C showed a negative coefficient of resistivity below room temperature, which gradually changed to positive above room temperature (45). The temperature at which the changeover occurred increased as the ionization of the donor impurity increased. This is believed to be caused by a change in conduction mechanism. 

Gu, H. and Shinoda, Y., (2000), Structural and chemical widths of general grain boundaries modification of local structure and bonding by boron-doping in P-silicon carbide , Interface Science, 8 (2/3), 269-278. 

Prior to analysis, the FCC catalyst samples were embedded in copper doped thermosetting epoxy to provide increased electrical conductivity. They were dry polished with silicon carbide to approximate cross-sections. 

Sea sand is primarily comprised of silicon dioxide (silica), which may be converted to elemental silicon (96-99% purity) through reaction with carbon sources such as charcoal and coal (Eq. 2). Use of a slight excess of Si02 prevents silicon carbide (SiC) from forming, which is a stable product at such a high reaction temperature. Scrap iron is often present during this transformation in order to yield silicon-doped steel as a useful by-product. 

Proton studies using MQ techniques have been made to determine the proton distribution in systems such as hydrogenated amorphous silica films (Levy and Gleason 1993a) and silicon carbide (Petrich et al. 1987). Hydrogen doping of carbon-based... 

Silicon carbide (SiC) is an attractive semiconductor material for high temperature electronic and electro-optic applications. From the device application point of view the thermal conductivity of SiC exceeds that of copper, BeO, A1203 and AIN. The actual value of the thermal conductivity can be varied with polytype and/or doping [1,2]. 

In the commercial semiconductor world of silicon (Si) devices, great importance is attached to diffusion and ion implantation. These processes play a key role in the local doping performance through windows in a thermally grown oxide film. Because the diffusion coefficients for most dopants in silicon carbide (SiC) are negligible, at temperatures below 1800°C, the development of ion implantation into SiC for microelectronic technology is of major importance. 

Acceptor dopants are introduced in the crucible either in elemental form or in the form of carbides. If a dopant is introduced in elemental form, it is placed in a special internal crucible with carbon or silicon carbide powder. This is required to prevent the dissolution of the crucible, in the case of aluminium doping, and to reduce the boron vapour pressure to the equilibrium value for the SiC-C system, in the case of boron doping. If elemental boron is placed in the vicinity of the substrate, this results in the formation of boron carbide on the crystal faces of SiC [46]. For moderate doping of crystals, grown at high temperatures, doped SiC sources also can be employed. 

Initial explanations of the extraordinary high-temperature stability of precursor-derived Si-B-C-N ceramics were presented previously by Jalowiecki et al. The authors investigated the microstmcture of boron-doped silicon carbonitride composites by HR-TEM and fotmd turbostratic BN(C) segregation occuring along grain boundaries of nano-sized silicon carbide and silicon nitride crystals. We suppose... 

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