Abstract
Arsenic profiles in plasma doped silicon wafers were traced by scattering of H+ and H+₂ ions at medium energies. Two wafers were doped with the same bias, gas pressure, total implanted dose and AsH₃ concentration. After implantation, the wafers were submitted to industrial cleaning processes and one wafer was subjected to an additional thermal treatment. Scattering spectra of single and molecular ion beams with the same energy per nucleon and charge state differed only by the energy broadening due to the break-up of the molecule, allowing depth profiling by calculation of the dwell time before the backscattering collision. On average, we observed a density reduction of 13% in the SiO₂ overlayer grown after the implantation process. In addition, the arsenic depth-profile determined were in close agreement with independent findings obtained by electron techniques.