Single crystal silicon has been implanted with low energy (20 keV) phosphorus ions and a comparison made of furnace annealing (which produces excellent solar cells) and rapid annealing using a radiant incoherent light source. The light source is used to anneal and activate implanted layers in the isothermal mode on a time scale of the order of seconds compared with the much longer furnace annealing times of several hours.
Initial results using the incoherent light source show a high dark current and inferior photoresponse. However a subsequent thermal treatment at 600°C for 10–15 minutes shows that the resultant photoresponse can approach that of the longer time furnace anneal. Transmission electron microscopy shows the formation of large voids (20–100 nm) after the initial annealing phase. These reduce in size after furnace annealing. This photoresponse may be related to this void formation.