Effect of Oxygen on Phosphorous Aluminum Gettering of Multicrystalline Silicon in Solar Cells

It is described that a series research of heavy phosphorous diffusion gettering, aluminum and combination of aluminum and phosphorous gettering (evaporation of aluminum on the back of the wafers) are used to fabricate multicrystalline silicon solar cells with different impurity concentration of interstitial oxygen. It is found that the minority carrier lifetime of the multicrystalline silicon wafers is improved greatly after getterring (by QSSPCD). The phosphorous/ aluminum co-gettering is found to be the most effective way in improving the minority carrier lifetime of the multicrystal- line silicon wafers. Moreover, when the concentration of interstitial oxygen is lower than 10 ppma, the effect of gettering is more evident.