Silicon carbide saturated

Figure 33.2 shows XPS spectra of the surfaces of the TMS plasma polymer film deposited on (Ar + H2) plasma-pretreated steel (a, b, c) and on O2 plasma-pretreated steel (d, e, f). As shown in the spectra, the surface of the plasma film is functional in nature with functional groups of C-OH, C=0, and Si-OH. Two films basically ended up with the same surface structure. This is also confirmed by XPS analysis of the film during the film aging in air after the film deposition, which indicated that the film surfaces were saturated with a fixed surface structure after a few hours of air exposure [4]. This is due to a well-known phenomenon that the residual free radicals of the plasma polymer surface reacted with oxygen after exposure to air [5]. Curve deconvolution of C Is peaks showed structures of C-Si, C-C, C-0, and C=0. The analysis clearly shows a silicon carbide type of structure, which is consistent with the IR results. The functional surfaces of TMS films provide bonding sites for the subsequent electrodeposition of primer (E-coat). 

Carbon tetrafluoride is an extraordinarily stable compound. It is the end product in the fluorination of any carbon-containing compound. A useful laboratory preparation, for example, involves the fluorination of silicon carbide. The SiF4 also formed is removed easily by passing the mixture through 20% NaOH solution. The CF4 is unaffected, whereas the SiF4 is immediately hydrolyzed the difference is due to the fact that, in CF4, carbon is coordinately saturated whereas silicon in SiF4 has 3d orbitals available for coordination of OH- ions in the first step of the hydrolysis reaction. 

Diamond has an excellent electron-carrier mobility exceeded only by germanium in the p-type and by gallium arsenide in the n-type. The saturated carrier velocity, that is, the velocity at which electrons move in high electric fields, is higher than silicon, gallium arsenide, or silicon carbide and, unlike other semiconductors, this velocity maintains its high rate in high-intensity fields as shown in Fig. 11.15. 

W von Muench, E Pettenpaul. Saturated electron drift velocity in 6H-silicon carbide. J Appl Phys 48 4823, 1977. 

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