Removal of hydrogen and deposition of surface charge during rapid thermal annealing

The submission of a hydrogenated oxide-passivated silicon wafer to a rapid thermal anneal (RTA) leads to a complicated change in effective lifetime τ eff . Within seconds, τ eff decreases rapidly before increasing to near its initial level, and then decreasing more slowly. The initial decline is shown to be due to hydrogen loss from the SiO 2 -Si interface, as is consistent with the literature. The recovery in τ eff is due to the deposition of surface charge, somehow related to the placement of the sample on an as-cut silicon baseplate within the RTA chamber; this surface charge can be removed by washing the sample in isopropanol. The mechanism behind the final decrease in lifetime is unknown.