Amorphous diamondlike films are deposited on Si wafer at temperature lower than 300 degrees C in a cathodic are plasma deposition (CAPD) system. Graphite plate with density 1.9 g/cm(3) was employed as the cathode target and the carbon source. NdFeB magnets with 1000 G strength were installed behind the graphite tar et to steer the motion of are spots on graphite. The are current was selected as low as 55 A in order to minimize the emission of microparticles from graphite target. The are spots observed were moving steadily on the graphite target with a speed of about 1.5 cm/s. O-2/Ar gas mixtures were introduced into CAPD system and the total pressure was controlled to be 10 mTorr. The effects of the addition of O-2, the rf self-bias (V-B) applied to Si wafer and the deposition temperature (T-S) on the quality of diamondlike films were investigated. It is concluded that the addition of O-2 is the key factor that contributed to the quality improvement of diamondlike films. The higher the partial pressure of O-2, the more significant is the influence of V-B and T-S on the quality improvement of diamondlike films.