We have investigated the electrical characteristics and junction depth and defect of ultrashallow junctions formed using plasma doping. Compared with ultralow energy boron ion implantation at 500 eV, the plasma doping process exhibits both a shallow junction depth and a low sheet resistance. The junction depths of the plasma-doped samples were 15 and 33 nm after annealing for 10 s at 900 and 950 degrees C, respectively. For the same junction depth, the sheet resistance of the B2H6 plasma-doped sample is an order of magnitude less than that of the 500 eV B ion implanted sample. Based on cross-sectional transmission electron microscope, deep level transient spectroscopy, and junction leakage current, the defects formed by the B2H6 plasma doping process can be completely removed by annealing at 950 degrees C for 10 s.