High hydrogen concentrations produced by segregation into p⁺ layers in silicon

Gallium-implanted p+ layers in Si were exposed to atomic hydrogen from a plasma. It was found that very large hydrogen concentrations, up to 7.5 times larger than the peak Ga concentration of 7×10 19/cm3, segregated into the p+ layer during treatment at 200°C. The shape of the hydrogen concentration profile was similar to that of the Ga profile. Ion channeling showed that the H atoms did not occupy simple high-symmetry sites in the lattice, and electron microscopy revealed the presence of extended {111} stacking fault defects associated with the layer of high hydrogen concentration. A mechanism to account for these findings is suggested.