It is found that one of the dominant parameters in determining the dangling-bond (DB) density in hydrogenated amorphous silicon (a-Si:H) films prepared by catalytic chemical vapor deposition (Cat-CVD), often called hot-wire CVD, is the catalyzer-surface area. a-Si:H films with an initial DB density of 4x10(15)cm(-3) and a saturated one after light soaking of 3x10(16)cm(-3) are prepared by Cat-CVD with a deposition rate of 11 Angstrom /s. "Catalytic plate" instead of the conventional wire is also proposed in order to suppress the heat radiation from the catalyzer while keeping the catalyzer surface area constant. (C) 2001 Elsevier Science B.V. All rights reserved.