Evaluation of the simultaneous use of Cp 2 VMe 2 and CpTiCl 2 N(SiMe 3 ) 2 as precursors to ceramic thin films containing titanium and vanadium: Towards titanium–vanadium carbonitride

Abstract

Ceramic thin films containing titanium, vanadium, carbon, oxygen and nitrogen were obtained on steel substrates at 873 K, under nitrogen and helium gases and at low pressure, by chemical vapor deposition (CVD) from two organometallic precursors, CpTiCl 2 N(SiMe 3 ) 2 and Cp 2 VMe 2 (Cp, cyclopentadienyl). Independent TG–DTA–MS and CVD studies of the two precursors showed their ability to co-decompose within compatible temperature and pressure domains. The mechanism of the reactions occurring inside the CVD apparatus was also approached by GC–MS and NMR analyses of the condensed decomposition products. CVD conducted under He gas confirmed that the formation of nitride resulted from the nitrogen atoms of the precursor, but the nitrogen content in the films remained lower than approx. 5%. Higher nitrogen contents (up to 12%) were only obtained when using ammonia as a carrier gas. Both precursors being air- and moisture-sensitive, high-purity CVD equipment was used to reduce oxycarbide formation. © 1998 John Wiley & Sons, Ltd.