Monitoring chemical vapour deposition of pyrocarbon by electron spin resonance

Pyrolytic carbon films were deposited on boron nitride substrates during pl ug-flow of a methane/argon gas mixture through a hot-wall tubular reactor a t 100 kPa and 1100 degrees C. Of particular interest is the time resolved d evelopment of chemical reactions within the free reactor volume, which is p rojected to the formed structures along the reactor axis. Spatially resolve d electron spin resonance (ESR) is used to characterize the deposited films . The width and asymmetry of the ESR line varies monotonously along the rea ctor axis by more than one order of magnitude within 25 mm. (C) 2000 Elsevi er Science S.A. All rights reserved.