Effect of end-of-range defects, arsenic clustering and precipitation on transient enhanced diffusion in As+ implanted Si

(001) CZ silicon wafers were implanted with As at 100keV to a dose of 1x10(15)/cm(2). The implant was amorphizing in nature and the peak As concentration was below the As clustering threshold. Subsequently, a second As+ or Ge+ implant at 30keV at doses of 2x10(15)/cm(2), 5x10(15)/cm(2) and 1x10(16)/cm(2) were performed, respectively, into the as-implanted samples. The samples with a double arsenic implant induce As clustering at the lower doses and As precipitation at the highest dose at the projected range. However, the samples with the Ge do not induce clustering or precipitation. The samples were annealed at 700 degrees C for various times to regrow the amorphous layer and to cause enhanced arsenic diffusion beyond the end-of range region. These samples were analyzed by SIMS and TEM. The difference in the defect evolution at the end-of-range region and TED beyond the end-of-range region between the As+ and Ge+ implanted samples was used to isolate the effects of As clustering and precipitation.