Nitrogen plasma ion implantation in silicon using short pulse high voltage glow discharges

A high voltage (HV) pulse generator based on Blumlein technology was used to implant nitrogen ions into silicon substrates by immersion in a plasma generated by the HV pulse itself. Working pressures, applied HVs and treatment times were varied. Elemental depth profiles determined by Auger electron spectroscopy showed deeper penetration for higher voltages and broader profiles for increased treatment times indicating higher diffusion, as expected. Penetration depths, however, were about half of the values calculated by the SRIM code, probably due to the short duration of the HV pulse. The high-resolution x-ray diffraction ω/2θ scans measured around the (0 0 4) Si Bragg reflection of implanted samples had shoulders in the lower ω side, indicating a lattice expansion in the direction normal to the surface. Dynamical diffraction theory of Takagi–Taupin was used to fit the measured spectra, thus finding the strain profiles in the implanted samples. Both maximum strain values and integrated strains increased for samples implanted with higher voltages and treatment times and were almost independent of pressure.