CHANNELING EFFECTS IN ION-IMPLANTATION IN SILICON

Channeling effects in ion implantation are reviewed comparing experimental data with Monte Carlo simulations. B, and P ions at energies ranging from 0.5 and 1 MeV were implanted along the [100], [111], and [110] axes or in a random direction of silicon wafers. Profiles were obtained either by secondary ion mass spectrometry or by spreading resistance analyses after a rapid thermal annealing procedure. The maximum penetration and the electronic stopping were determined as a function of the beam energy and axial directions. A semiempirical approach based on the Oen Robinson formula is proposed to simulate the experimental data. Isoconcentration contour lines at the substrate doping level were obtained by a new two-dimensional delineation technique based on spreading resistance profiling. The lateral distribution of ions implanted in a random direction is always broader than that of ions implanted with the same energy along the [100] axis. These results are correlated to the reduced nuclear encounters experienced by an ion moving in a channel with respect to that one moving in a random trajectory