THE INFLUENCE OF FLUORINE ON BORON-ENHANCED DIFFUSION IN SILICON BY BF2-TEMPERATURE RAPID THERMAL ANNEAL( IMPLANTATION THROUGH OXIDE DURINGHIGH)

BF2+ implantation through a sacrificial oxide for the formation of p()/n shallow junctions is frequently applied in device fabrication. The effects of fluorine on boron diffusion in and out of a silicon substr ate during nitrogen-ambient high temperature rapid thermal annealing h ave been studied. By comparing B and BF2 implanted substrates, it is s hown that fluorine out-diffusion during high temperature annealing coi ncides with enhanced boron out-diffusion into the oxide and suppressed boron diffusion into the substrate. In particular, when fluorine accu mulated at the end of range dislocation loops is driven out of the bul k, shallower junctions are observed.