Enhanced thermal donor formation in silicon exposed to a hydrogen plasma

Czochralski silicon samples have been heated at temperatures between 350-450 degrees C in a hydrogen plasma. Thermal donors are generated at about five times the rate found after furnace annealing, even if the ambient is hydrogen gas. The final donor concentration is comparable for the two types of processing. There is no significant evidence for hydrogen passivation effects and donors are not produced in plasma treated FZ silicon. Heating samples in an argon plasma does not enhance the rate of donor formation. Possible mechanisms for the enhancement are outlined briefly.