A PACVD apparatus was designed and fabricated at Shizuoka University in order to prepare high-pure boron coating films. In,as concentration, substrate temperature and CVD input power, have the present study, some parameters, especially feeding been optimized to prepare pure boron coating films. It was found that the purity of boron coating film was controlled by the decaborane concentration of feeding gas and substrate temperature during the PACVD process, and each optimized values were 0.4 and 473 K, respectively. The atomic composition of boron in the boron coating film under the optimized condition has been achieved to be 0.94. (c) 2004 Published by Elsevier B.V.