Shallow arsenic profiling using medium energy ion scattering (MEIS)

The minimum feature size of integrated circuits shrinks rapidly, which requires analysis with an enhanced depth resolution of dopants in their shallow source-drain regions and their extensions. Rutherford backscattering spectroscopy (RBS) combining a medium energy ion scattering (MEIS) with a detector of improved energy resolution provides the depth resolution or 2.4 4.0 nm at a depth of 10 - 20 nm. Arsenic ions were implanted into Si at 5 keV to a dose of 1 × 10¹⁵ ions/cm² and annealed by rapid thermal annealing (RTA) at 1050°C for 5 s. Depth profiling results using MEIS were compared with those of secondary ion mass spectroscopy (SIMS) and glancing angle RBS by MeV energy He ions.