Solar energy materials and solar cells vol:34 issue:1-4 pages:237-241
In this work the improvement of the quality of the electromagnetic cold crucible cast multicrystalline silicon (EMC) material produced by Sumitomo Sitix Co. (SCC, previously Osaka Titanium Co.) by hydrogen plasma is investigated with the final goal of realizing solar cells with the maximum possible efficiency. Two different hydrogen passivation techniques are implemented: hydrogen passivation by means of rf (radio frequency) plasma treatment and hydrogen passivation using microwave induced remote plasma treatment. By combining the oxide surface passivation and hydrogen passivation by remote plasma from the front side and by rf plasma from the back side, a significant improvement in short-circuit current, in open-circuit voltage, and in fill factor is obtained. A maximum efficiency of 16% on 2 x 2 cm(2) cells and of 14.5% on 10 X 10 cm(2) cells is achieved. This 16% efficiency is the highest ever reported on EMC multicrystalline silicon.