Electrical activation of ultra-shallow B and BF2 implanted silicon by flash anneal

Ultra-shallow ion implanted Si wafers, both with and without Ge pre-amorphization, were annealed using xenon arc flash lamps. The duration of flash illumination was controlled between 1 ms and 20 ms. Changes in sheet resistance and dopant profiles after flash anneal were measured and investigated, along with crystal defect densities. Sheet resistance was measured using a four-point probe. Dopant depth profiling and defect characterization were done using secondary ion mass spectroscopy (SIMS) and cross-sectional transmission electron microscopy (XTEM). Sheet resistance values of 250-350 Ω/sq. at a junction depth of 24 nm (at B concentration of 1.0 × 1018 cm−3) were achieved. No significant dopant diffusion was observed after the Xe arc flash lamp annealing.