Formation of carbon particles due to interaction between plasma and carbon fiber composite (CFC) or graphite targets has been studied using an electron cyclotron resonance (ECR) plasma device. The interaction produces two kinds of particles: small ones have a size of 2-25 nm, spherical shape; large ones have a size above 100 nm, irregular shape. Total amount and average size of small particles tend to decrease with increasing sheath voltage V-s between plasma and the carbon targets from 14 V to 214 V. Optical emission intensities of C and CH decrease with increasing V-s, while gas absorption rate to the target increases. These results suggest that carbon-containing species emitted from the carbon targets contribute to formation of small particles. (c) 2005 Elsevier B.V. All rights reserved.