EFFECT OF DEPOSITION TEMPERATURE AND GROWTH-RATE ON THE BOND STRUCTURE OF HYDROGEN FREE CARBON-FILMS

The effect of deposition temperature and growth rate on the bond struc ture of hydrogen free carbon films has been investigated. A sharp tran sition temperature of the sp(3) content of the carbon films as a funct ion of deposition temperature has been reported several times. The val ue of this transition temperature has varied from 150 to about 300 deg rees C depending on the growth mechanism. In this article, high values varying from 300 to 400 degrees C for the transition temperature are reported. High momentary growth rates of up to 2000 nm/s have been obt ained by using pulsed vacuum are deposition. The transition temperatur e has been observed to depend on the momentary growth rate of the carb on film. The transition has been explained to be a relaxation process which includes diffusion of carbon atoms at the near surface. The resu lts have been analyzed by using a model which was originally developed for radiation enhanced diffusion. An activation energy of 0.65 eV was obtained. The model also predicts qualitatively the transition temper atures in the case of the lower deposition rates reported in literatur e. For the frequency factor of the diffusion coefficient a value of th e order of 10(-8) Cm-2/s was obtained. (C) 1998 American Institute of Physics.