Hydrogen introduction and hydrogen-enhanced thermal donor formation in silicon

Hydrogen has been introduced from a rf plasma into Czochralski Si at 275 °C. Most of the hydrogen is trapped near the surface where it forms Si—H bonds, but a small fraction diffuses into the Si. This fraction enhances oxygen-related thermal donor (TD) formation rates in a diffusionlike profile during subsequent furnace anneals between 350 and 400 °C. A hydrogen concentration that is only a few percent of the oxygen concentration is sufficient to enhance the TD formation rate, indicative of a hydrogen-catalyzed process. Maximum concentrations for TDs after annealing at 400 °C exceed that for retained hydrogen. A mechanism of hydrogen diffusion through oxygen traps and correlated hydrogen-promoted oxygen diffusion is proposed to explain the enhanced TD formation rates.