Technical progress of high-quality, Ga-doped multicrystalline silicon wafers and solar cells

Average carrier lifetimes above 400 /spl mu/s are realized after proper P-diffusion and hydrogen passivation on Ga-doped multicrystalline Si wafers cut from a 70 kg ingot where the response to P-diffusion and hydrogen passivation is pronounced. High carrier lifetimes are realized over the whole ingot with minimum values of 20 /spl mu/s in the top of the ingot indicating the possible use of about 85% of the ingot for solar cell production. The effect of resistivity variation on solar cells conversion efficiency is investigated by means of PC-1D simulation. Conversion efficiencies above 15.5% are realized by utilizing more than 80% of the ingot. Efficiencies as high as 16% are realized on wafers with resistivities higher than 5/spl Omega//spl middot/cm demonstrating high conversion efficiency in high-resistivity, p-type multicrystalline silicon wafers.