Carbonitride films

Brennfleck, K., Dietrich, M., Fitzer, E., andKehr, D., Chemical Vapor Deposition of Superconducting Niobium Carbonitride Films on Carbon Fibers, Eroc. 7th Int. Conf. on CVD, (T. Sedgwick andH. Lydtin, eds.), pp. 300-314, Electrochem Soc., Pennington, NJ 08534 (1979)... 

In amido derivatives used as precursors to nitrides, the presence (e.g. in V(NEt2)4) of alkyl groups that could self-eliminate to alkenes, was not sufficient to ensure nitrogen incorporation into the films, and addition of NH3 was necessary. More important was control of the molar fraction of V(NEt2)4 and NH3 in the gas phase, which allowed the formation of vanadium carbonitride films with variable and adjustable stoichiometry. 

Bis-trimethylsilylcarbodiimide is used as a monomer in the synthesis of silicon car-bodiimide polymers used as precursors for ceramics. Also, hard silicon carbonitride films are obtained by RF plasma-enhanced chemical vapor deposition of bis(trimethyl-silyl)carbodiimide. ... 

Nitrogen ion implantation of the carbonitride films was also carried out to further increase the nitrogen percentage in the film to obtain the desired stoichiometry of P-C N. For carbonitride films deposited by cathodic arc, no evidence... 

Fig. 22 RBS spectra of carbonitride films deposited, at different temperatures, using IBAD technique.

However, in recent times, there have been several reports on synthesis of the crystalline form of carbonitride. Zhang et al. " synthesized crystalline carbonitride films with large crystalline grains up to 10 pm (from SEM and XRD spectra) in size by RE plasma assisted hot filament chemical vapor deposition. Li. et al. claimed to have synthesized poly crystalline C3N4 films (from XRD data) at ambient temperature by RE diode sputtering. Erom Auger electron spectroscopy, the N/C ratio was computed to be 1.33 as required for C3N4 stoichiometry. 

However, in some reports, electron diffraction patterns of the carbonitride films that were indexed as P-C3N4 structure " were later observed to fit to other carbon phases. It was also shown that the published diffraction... 

Figure 22 shows RBS spectra of amorphous (Raman spectra similar to amorphous diamond like films) carbonitride films deposited at different temperatures using IBAD. Using this technique, maximum nitrogen incorporation was 33% as compared to 57% required for P-C3N4 stoichiometry. The XPS spectra (C Is and N Is) of the film with 33% nitrogen are shown in Figure 23. From these spectra the percentage of single bonded carbon and nitrogen is obtained...

Fainer NI, Kosinova ML, Rumyantsev YM, Kuznetsov FA (1999) RPECVD thin silicon carbonitride films using hezamethyldisilazane. J de Physique IV, 9, Pr8-769-... 

Y M Rumyantsev, A N Golubenko and F A Kuznetsov, LPCVD boron carbonitride films from triethylamine borane, Pr8-915-921, 1999, with permission from EDP Science. 

As a consequence of their superior physical and chemical properties, silicon nitride and silicon carbonitride films have become increasingly important for both structural and microelectronic device applications. Chemical vapor depositions (CAH)) has become a major technique for the synthesis of these thin film materials flO]. 

The chemical structure of the films and particularly the incorporation of hydrogen were studies by FTIR (Perkin Elmer 1760). Fig. 8 shows infrared transmittance spectra of silicon carbonitride films (a) and silicon nitride films (b) deposited at 1123 K. The clusters of absorption peaks that appear in both spectra in the 1300 to 1940 and 3320 to 3900 wavenumber (cm i) regions are attributed to atmospheric moisture. CO2 is also detected at around 2345 cm i. For spectrum (b), the strong band at 847 cm-i indicates the formation of amorphous silicon nitride [161. The much weaker peak at 3326 cm i which is due to a N—H stretching vibration indicates the existence of N—H bonds in the films. The Si—N band at 847 cm i appeared to be broadened near its base line around 1173 cm i. This is due to the existence of N-H bonds which exhibit another bending mode at 1170 cm l All the films displayed similar spectra, and there was no indication of an Si—H bond in silicon nitride. In addition to the stro line at 837 cm, resulting from the fundamental stretching of silicon carbonitride [17], the main difference between spectra (a) arid (b) is the presence of a weak Si—H band, which is observed to be more intense in the films deposited below 1123 K. None of the films exUbited the C—H band around 2900 cm i, which is present in the IR spectrum of the precursor. 

Pike, G., Pierson, H. O., Mullendore, A., and Schirber, J., Superconducting Thin Film Niobium Carbonitrides on Carbon Fibers, / / . Polymer Symp., No. 29, pp. 71-81, John Wiley Sons, New York (1976)... 

Pierson, H. O., Titanium Carbonitride Obtained by Chemical Vapor Deposition, Thin Solid Films, pp. 41-47 (1977)... 

Titanium(IV) guanidinato complexes, which are easily accessible by the standard synthetic routes (cf. Section III.B.2), have been studied as precursors to titanium carbonitride. Thin films of titanium carbonitride were obtained by low-pressure chemical vapor deposition of either [(Me3Si)2NC(NPE)2]TiCl(NMe2)2 or [Me2NC(NPE)2]2TiCl2 at 600 Most recent developments in this field... 

The best results were obtained with compound 21 that exhibited high vapor pressure and low decomposition temperature (<523 K). Various CVD conditions were applied and gave in all cases shiny, dark-brown deposits.43 XRD and XPS analyses of the deposits indicated the presence of a vanadium carbonitride phase with little contamination from oxygen and free carbon. The films were less adherent on steel substrates than on silicon ones. The steel substrates seemed to suffer corrosion due to the presence of Cl-containing species. We had noticed the same feature in the case of Cl-containing precursors to vanadium carbide. Therefore, in order to increase the volatility of compound 23 and to reduce the Cl content of the molecule, we prepared compounds 24 and 25. Unfortunately, the yields obtained in their syntheses were much too low to permit TG and CVD experiments. 

Among the physical techniques, reactive sputtering is used most frequently because it produces films of high purity with relative ease and good reproducibility. In addition, many compound types can be prepared (carbides, nitrides, oxides, carbonitrides, oxicarbonitrides) including metastable phases. 

We have also observed the formation of excess carbon when using CpTiCl2[N(SiMe3)2] (9).35 This compound was shown to form titanium carbonitride thin films on silicon and steel substrates at 823 K. The presence of Cl in the molecule induces a lower adherence of the films on steel substrates versus silicon. In order to reduce this problem, we have prepared compound 10. Unfortunately, the very low chemical stability of this compound prevented us from carrying out thermoanalytical and CVD studies.29... 

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. 

Another amorphous phase of carbonitride, C N phase with sp bonding, was shown to be a stable phase which exhibits high electrical resistivity and thermal conductivity similar to that of diamond-like films. The diamond-like properties and non-diamond-like bonding make C N an attractive candidate for applications such as thermal management in high-performance microelectronics. 

Silicon Nitride Silicon Carbonitride Thin Films From Silazane Oligomers... 

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