Hydrogen passivation of Interstitial Iron in Silicon by Annealing with PECVD Silicon Nitride Films

Abstract

This paper reports on the effective passivation of interstitial iron in p-type boron-doped silicon via annealing with plasma-enhanced chemical vapour deposited (PECVD) silicon nitride films. The concentration of interstitial iron was shown to reduce by more than 90% after a 30-minute anneal at 600 – 900oC with the silicon nitride films present. The most effective hydrogenation of iron was found to take place at 700oC, where more than 99% of iron was passivated after 30 minutes. Results show that the observed reductions in the interstitial iron concentrations are not likely to be caused by the precipitation of iron at structural defects by a hydrogen-enhanced diffusivity of iron, as has previously been suggested.