Heavy B atomic-layer doping in Si epitaxial growth on Si(100) by electron-cyclotron-resonance (ECR) Ar plasma enhanced chemical vapor deposition (CVD) has been investigated. By B atomic-layer formation and subsequent Si epitaxial growth on Si(100) without substrate heating, atomic-layer doping is achieved. Most of the incorporated B atom amount of about 7 x 10(14)cm(-2) in the B atomic-layer doped Si film is confined within about 2 nm-thick region. For Si cap layer deposition under lower energy plasma condition, the incorporated B atom amount is scarcely changed. On the other hand, in higher energy plasma irradiation condition, it is found that B atoms on Si(100) desorb due to Ar(+) ion irradiation. These results demonstrate that lower energy plasma conditions are effective to perform heavy B atomic-layer doping. (C) 2009 Elsevier B.V. All rights reserved.