Making a thinner wafer is a simple way of reducing the production costs of silicon solar cells. However, supporting this thin wafer in some way is necessary to protect the solar cell from breakage. A cheap substrate needs to be developed and attached to the thin silicon solar cell with aluminum paste. Silicon solar cells of 150 μm thickness with a sintered substrate on the back side show a 5.4% conversion efficiency as a solar cell. Compared to commercial silicon cells, a lower short circuit current (Jsc) is obtained. This might be due to the poor conduction in the back layer of aluminum which is absorbed into the supporting substrate during the annealing for bonding. Another way of lowering wafer costs is to apply the extrinsic gettering method to the silicon wafers made from cheap silicon raw materials which possibly contain metal impurities. Damage induced during the slicing process of the silicon wafers with wire saws is found to generate dislocations after the oxidation process which may contribute to the gettering. Therefore, without any additional process, cheaper raw materials are expected to be used for the cost reduction of the silicon wafers.

Keywords: saw damage, gettering, bonding, solar cell