Abstract: Carbon fibers were synthesized on Si substrates deposited with buffer layers （Ta or Ti） andNiFe catalyst layers by using bias-enhanced hot filament chemical vapor deposition method, using CH₄,H₂ or mixed gases containing NH₃ as reaction gases. Growth and structure of carbon fibers were inves-tigated by scanning electron microscopy. It is found that different deposition conditions greatly affectthe growth and structure of carbon fibers. Without glow discharge, it is difficult to grow carbon fibers at low substrate temperature, the bent carbon fibers can be grown at higher substrate temperature. Withglow discharge, aligned carbon fibers can be obtained. The influence mechanism of different depositionconditions on growth and structure of carbon fibers is discussed in details.