Sputtering carbon nitrides

M.A. Monclus, D.C. Cameron, A. Chowdhury, R. Barkley, M. Collins, Investigation of the valence band states of reactively sputtered carbon nitride films. Thin Solid Films 355,79-84... 

Up to the present, a number of conventional film preparation methods like PVD, CVD, electro-chemical deposition, etc., have been reported to be used in synthesis of CNx films. Muhl et al. [57] reviewed the works performed worldwide, before the year 1998, on the methods and results of preparing carbon nitride hlms. They divided the preparation techniques into several sections including atmospheric-pressure chemical processes, ion-beam deposition, laser techniques, chemical vapor deposition, and reactive sputtering [57]. The methods used in succeeding research work basically did not... 

Wang, X., Martin, P. J., and Kinder, T. J., Optical and Mechanical Properties of Carbon Nitride Films Prepared by Ion-Assisted Arc Deposition and Magnetron Sputtering, Thin SolidFilms, o. 256, Ho. 1-2,1995,pp. 148-154. 

Abstract DC co-sputtered Carbon-Nickel and Carbon-Nitride-Nickel thin films were... 

In most efforts, the films produced were either amorphous, or their nitrogen content was less than the target of 57%. D. Li et al. [184] using a magnetron sputtering system produced crystalline carbon nitride/titanium nitride composite coatings with a reported hardness of 55 GPa. 

Lu TR, Kuo CT, Yang JR, Chen LC, Chen KH, Chen TM. High purity nano-crystaUine carbon nitride films prepared at ambient temperature by ion beam sputtering. Snrf Coat Technol 1999 115 116-22. 

Marumo Y, Yang Z, Chung YW. Optimization of properties of carbon nitride and CN /TiN coatings prepared by single-cathode magnetron sputtering. Surf Coat Technol 86-87 586, 1996. 

Hammer P, Baker MA, Lenardi C, Gissler W. Ion beam deposited carbon nitride films Characterization and identification of chemical sputtering. Thin Solid Films 290-291 107, 1996. 

Coatings of refractory carbides and nitrides and more recently carbon and DLC are used extensively in decorative applications on jewelry, eyeglasses, and similar products in attractive colors such as gold (TiN) and metallic grey, or charcoal (DLC, CrN, and TaN). They provide a surface which is hard and wear resistant, sweat resistant and, in the case of gold, less costly. They are usually applied by cathode sputtering and less frequently by CVD. 

Thin films of carbides and nitrides of Group 6 metals were synthesized by reaction of a metal film with a reactive gas at high temperature and by reactive sputtering. The phases obtained depended on the experimental conditions. High temperatures metastable phases (/i-WC, v and 6-MoC]. ) were obtained by reactive sputter deposition of films. The carbon concentration in such films depended on the temperature of the substrate and on the pressure. In some cases ordered sublattices of carbon and nitrogen were observed and epitaxial relationships between the deposit and the substrate were studied. 

Following all the results presented here, there seems to be a strong difference between the formation of carbides and nitrides by reactive sputtering if the substrate temperature increases, the nitrogen concentration in the film decreases while the carbon concentration increases. 

A new method of interpreting Auger electron spectroscopy (AES) sputter profiles of transition metal carbides and nitrides is proposed. It is shown that the chemical information hidden in the shape of the peaks, and usually neglected in depth profiles, can be successfully extracted by factor analysis (FA). The various carbide and nitride phases of model samples were separated by application of FA to the spectra recorded during AES depth profiles. The different chemical states of carbon, nitrogen and metal were clearly identified. 

Nagai and co-workers prepared alumina-supported niobium nitride from the eVD of NbCls, using a mixture of NH3 and H2 as a nitridation gas at 823 K under reduced pressure (65). NbN thin film of submicrometer thickness on carbon plate was prepared via the RF-sputtering method (RF power of 2.5 W/cm ) with a Nb plate and N2 atmosphere under vacuum chamber (66). A NbN thin film retained the fine particles of 100 nm. 

With this respect, the work from Atanasoski and coworkers is promising (compare section Transition Metal Carbides, Nitrides and Chalcogenides ) [35], By performing a heat treatment of their sputtered C-N iFe Aims, the activity was drastically enhanced but still much lower compared to macrocycle-based catalysts. However, when titanium carbide was used as support instead of carbon, a high stability was obtained. The fact that by changing the support, an essentially better durability was obtained is an important result as it shows that even for catalysts based on molecular centers, alternative support materials can be utilized and that the interaction between the support and the catalytic centers might be cmcial for the optimization of those catalysts for a fuel cell application. 

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