A vacuum casting method was attempted to produce cheap poly-Si wafers ready for solar cell fabrication without any cutting
or slicing. However, the 5 × 5 cm2 lab scale cast poly-Si wafers contained high carrier concentrations, above 3 × 1017/cm3, an...
A vacuum casting method was attempted to produce cheap poly-Si wafers ready for solar cell fabrication without any cutting
or slicing. However, the 5 × 5 cm2 lab scale cast poly-Si wafers contained high carrier concentrations, above 3 × 1017/cm3, and
crystalline defects like grain boundaries and gas porosity. We carried out a set of vacuum casting experiment in order to
identify the main sources of impurities during vacuum casting and investigated the impurities in the cast poly-Si wafers. The
efficiency of the test solar cells fabricated on the cast poly-Si wafers was below 1.0% whereas the efficiency of the solar cell
fabricated on the wafer sliced from starting Si was 5.5%. The low efficiency of the test cells was attributed to high carrier
concentrations and gas porosity inside the cast poly-Si wafer.