The effect of excimer laser annealing and rapid thermal annealing on B redistribution in B-implanted Si was studied by secondary ion mass spectrometry and spreading resistance probe. B was implanted with an energy of 1keV and a dose of 1016/cm2 forming a distribution with a width of 20–30nm and a peak concentration of about 5 x 1021/cm3. It was found that excimer laser annealing with 10 pulses of the energy density of 850mJ/cm2 resulted in a uniform B distribution over the excimer laser annealing-molten region with an abrupt profile edge. Spreading resistance probe measurements demonstrated good activation of the implanted B after excimer laser annealing, with the concentration of the activated fraction (circa 1021/cm3) exceeding the solid solubility level. Rapid thermal annealing (30s, 1100C) of the as-implanted and excimer laser annealing-treated samples leads to a diffusion of B with diffusivities exceeding the equilibrium one and the enhancement was similar for both of the samples. It was also found that rapid thermal annealing decreased the activated B in the excimer laser annealing-treated sample to the solid solubility limit (2 x 1020/cm3). The similarity of the B diffusivity for the as-implanted and excimer laser annealing-treated samples suggested that the enhancement of the B diffusivity was due to so-called B-enhanced diffusion.

Boron-Enhanced Diffusion in Excimer Laser Annealed Si. E.V.Monakhov, B.G.Svensson, M.K.Linnarsson, A.La Magna, V.Privitera, G.Fortunato, L.Mariucci: Materials Science and Engineering B, 2004, 114-115, 114-7