n–p Junction formation in p-type silicon by hydrogen ion implantation

Hydrogen ion implantations at an energy of 250 keV and a dose of 3×1016 cm−2 were applied to float zone, Czochralski grown silicon wafers and to multicrystalline samples. It was found that after annealing at 350°C<T<550°C for 1 h a n–p junction is formed and a photovoltaic behaviour is observed. Spectral responses show that the photocurrent in the near infrared part of the spectrum is comparable to that given by a standard silicon solar cell. The depth of the junction is about 2 μm and C–V measurements show that the junction is graduated. Hydrogen plasma immersion leads to similar results. The conversion of p- to n-type silicon is explained by the formation of shallow donor levels associated to a high concentration of hydrogen.