Thermochemical stability of silicon–oxygen–carbon alloy thin films: A model system for chemical and structural relaxation at SiC–SiO2 interfaces

Abstract

Alloy thin films of hydrogenated silicon-oxygen-carbon ͑Si,C͒O x xϽ2, were deposited and analyzed in terms of changes in structure and bonding as a function of rapid thermal annealing between 600 and 1100°C using a combination of Fourier transform infrared spectroscopy, Raman scattering and high-resolution transmission electron microscopy. Results showed that three structural/chemical transformations took place upon annealing. The initial reaction ͑600-800°C͒ involved the loss of hydrogen bonded to both silicon and carbon. At intermediate temperatures ͑900-1000°C͒ a Si-O-C type bond was observed to form, and subsequently disappear after annealing to 1050°C. The formation of ordered amorphous-SiC regions, nanocrystalline-Si regions, and stoichiometric, thermally relaxed SiO 2 accompanied the disappearance of the Si-O-C bond at the 1050°C annealing temperature. Using this alloy as a model system, important information is obtained for optimized processing of SiC-SiO 2 interfaces for device applications.

Review on the physicochemical treatments of rice husk for production of advanced materials

“…As the temperature is increased from 1240 to 1275ºC,a change in absorption at 1100 cm −1 (corresponding tothe vibration of Si−O bond) with respect to that at 900cm −1 (Si−C−O) is observed.There tends to be stronger absorption at 900 cm −1 for the samples heat-treatedto higher temperature, or Fe pretreated. The absorptionratios of the bands Si−O/Si− C− O may be indicative of the progressive transformation from silica to SiC [201,202].…”

Photoluminescent properties of oxidized stochiometric and carbon-rich amorphous Si1-xCx:H films

“…The spectrum of as-deposited sample is composed by strong absorption bands at 780 cm -1 (Si-C stretching) and Table. The absorption band at 1010 cm -1 in a-Si 1-x C x :H films is commonly ascribed to rocking/waging vibration modes in CH 2 radicals bonded to silicon atoms -Si-CH 2 -Si [23][24][25][26][27]. But it is well known that the main absorption band in silicon sub-oxide SiO x (x < 2) is also located at 1000…1400 cm -1 depending on x [20]. Residual oxygen contamination in our films was estimated using Auger electron spectroscopy to be up to 7…10 at.%, so that the contribution of Si-O vibrations should be taken into account.…”

Silicon oxycarbide glass for the immobilisation of irradiated graphite waste

“… Long-lived 14 C is the major radio-isotope present in the graphite; mainly generated from nitrogen impurities and neutron capture, and with a half-life of 5730 years, it is a dangerous -emitter that can be easily ingested as 14 …”

“…The main drawback to this method is the large volume of space it will take up in a GDF, where space will be at a premium, and therefore may be prohibitively expensive. Incineration has also been considered, however this will release 14 CO2 into the lower atmosphere and although the amount of 14 C released to air would be relatively low compared to the amounts generated in the upper atmosphere by natural processes, it is not viewed as a viable solution [5].…”

“…and a range of applications have identified in electroceramics, coatings, strong glass fibres and thin films [12,13,14]. Although the processing atmosphere has to be carefully controlled for oxycarbide glass production the possibility of bonding the graphitic carbon directly into the glassy matrix means that these glasses are potentially attractive for the immobilisation of irradiated graphite.…”