© 2019 The Japan Society of Plasma. To deposit stable a-Si:H films at a high deposition rate (DR), we have studied time evolution of DR and amount of cluster incorporation (R) into films as a parameter of gas velocity, in the downstream region of a multi-hollow discharge plasma chemical vapor deposition reactor; because a-Si:H films containing less cluster incorporation show high stability. For a low gas velocity of 0.18m/s, clusters are trapped between the multihollow electrode and the substrate and the trapped clusters absorb clusters and such absorption suppresses the cluster incorporation into films. By utilizing this phenomenon, we have realized a quite low R = 1.3 at a high DR = 0.06 nm/s.