Activation Energy for the Hydrogenation of Iron in P-Type Crystalline Silicon Wafers

The rate at which atomic hydrogen from silicon nitride films passivates interstitial iron in crystalline silicon has been measured at various temperatures. Both conventional quartz tube furnace annealing and rapid thermal annealing (RTA) were used to drive the hydrogen into the silicon wafers. The results allow an estimation of the activation energy for the hydrogenation process. For both annealing methods, this energy was found to be much larger than the migration enthalpy of atomic hydrogen in silicon. This suggests that the hydrogenation process is not diffusion-limited. Rapid thermal annealing was found to yield faster hydrogenation than conventional processing, and the results hint at a reduced activation energy as well. Over the temperature range 700-900 degC, hydrogen was found to passivate approximately 80% of the initial interstitial Fe atoms after 140 s of RTA