Plasma immersion ion implantation (PIII) is an established technique in some niche microelectronics applications, such as synthesis of silicon on insulator. In other applications, such as shallow junction formation by plasma doping, trench doping, and others, PIII possesses unique advantages over conventional techniques. In the last few years, there have been significant breakthroughs in these areas. Recent developments in plasma doping, direct-current plasma immersion ion implantation that excels in planar sample processing, PIII of insulating materials, as well as plasma surface modification of biomaterials are reviewed in this article. (C) 2004 American Vacuum Society.