HARNESSING REVERSE ANNEALING PHENOMENON FOR SHALLOW P-N-JUNCTION FORMATION

Monocrystalline silicon was implanted with 60 keV fluorine and 20 keV boron ions and annealed. Carrier profile, fluorine and boron redistrib ution, and the parameters of p(+)-n junctions were investigated. In io n implanted Si two specific regions were observed in which peculiariti es in carrier concentration, resistivity, and F atoms redistribution o ccurred. It was reasoned that the ''under-surface'' specific region is enriched with vacancy-type defects while the ''amorphous/crystalline (a/c) interface'' region is enriched with interstitial type defects. A fter annealing at a temperature corresponding to the reverse annealing phenomenon, boron atoms were activated in the ''under-surface'' and d eactivated in the ''a/c interface'' region. The possibility of PMOS tr ansistor fabrication with ultrashallow p(+)-n junction (60 nm) and low leakage current by F++B+ implantation and low temperature (600-700)de grees C, annealing by using this phenomenon was demonstrated. (C) 1997 American Institute of Physics.