COMPARISON OF SECONDARY-ION MASS-SPECTROMETRY PROFILING OF SUB-100 NMULTRASHALLOW JUNCTIONS USING NO2-2(+) SPUTTERING( AND O)

Secondary ion mass spectrometry (SIMS) with low energy sputtering is u sed to characterize ultrashallow-dopant profiles. Molecular ion sputte ring species help reduce the mixing depth of the sputtering process an d the broadening of the measured dopant distributions. The depth resol ution of NO2+ and O-2(+) primary beams at 2 keV net acceleration and 5 5 degrees incidence angle to the sample are compared by the measuremen t of low energy ion implanted dopant distributions. The sputtering con ditions result in a 380 eV/sputtering particle (normal to the sample s urface) for NO2+, and a 570 eV/sputtering particle for O-2(+). Measure ments of 1 and 2 keV BF2, as well as 5 keV As implants show trailing e dge slopes of 2.6 nm/dec for the I keV BF2, and 5.5 nm/dec for arsenic . The pre-equilibrium region at the near-surface of the sample is show n to be similar for NO2 and O-2, indicating that chemical segregation effects of the nitrogen in the sample are not detrimental to the profi le accuracy. (C) 1998 American Vacuum Society.