Si ultrashallow p+n junctions using low-energy boron implantation

Ultrashallow boron-doped junctions in silicon have been investigated using secondary-ion mass spectroscopy and four-point probe technique. The junctions were obtained by implanting B+ ions into n-type Si(100) at 200 eV to doses of 1.5×1014 and 6×1014 cm−2 and at substrate temperatures in the range 30–900 °C during B implantation. Both post-implantation in situ annealing by electron bombardment heating and rapid thermal annealing in a separate system were employed. The results show that sub 20 nm p+n junctions are obtained without the need for further processes such as preamorphization and high-temperature annealing.