Effect of thermal annealing on minority-carrier lifetimes in multicrystalline Si wafers

Effects of high-temperature annealing conditions on minority-carrier-lifetime variation have been investigated for multicrystalline Si wafers. Lifetime recovery peaks appear obviously at temperatures over 1000°C for the multicrystalline Si wafers, which is the same as for FZ and CZ single wafers. Bulk lifetimes degrade after a further long-time annealing in oxygen. This suggests that there exists the filling of vacancies with interstitial Si atoms generated at the Si surfaces during high-temperature annealing.