The positive-plasma-bias (PPB) method has been explored as a new option for the plasma-based ion implantation and deposition (PBII&D). In the PPB method, plasma is biased positive with respect to a target which is at ground potential. While it offers benefits such as handling of target during PBII&D processing and in-situ process monitoring, special considerations are needed to meet the necessary PPB conditions. In the present paper, fundamentals and applications of the PPB method that has been performed for years by the author's group are presented: First the working principle, geometry, potential and current distributions are explained. Then special features, possible merits and demerits are discussed. Finally the environment-friendly plasma cleaning and the dual-plasma ion process for insulator processing are presented as applications of the PPB method.