Growth and characterization of n-type polycrystalline silicon ingots

n-type polycrystalline silicon ingots were grown by directional solidification, and the grown ingots were sliced to wafers. The wafers were subjected to phosphorus gettering and hydrogen passivation. The minority carrier lifetimes of wafers before and after the processes were measured. The average lifetimes of the wafers after both the processes were improved by a factor of 2–3 times compared to those of as-grown wafers. The wafers were etched with a Secco solution to detect crystallographic defects. The effect of phosphorus gettering in the region where many etch-pits were observed is lower than that in the other region. On the contrary, the effect of hydrogen passivation in the region where many etch-pits were observed is higher than that in the other region.