BOOSTING THE EFFICIENCY OF SOLAR-CELLS FABRICATED ON ELECTROMAGNETIC COLD CRUCIBLE CAST MULTICRYSTALLINE SILICON BY MEANS OF HYDROGEN PASSIVATION

In this work the improvement of the quality of the electromagnetic col d crucible cast multicrystalline silicon (EMC) material produced by Su mitomo Sitix Co. (SCC, previously Osaka Titanium Co.) by hydrogen plas ma is investigated with the final goal of realizing solar cells with t he maximum possible efficiency. Two different hydrogen passivation tec hniques are implemented: hydrogen passivation by means of rf (radio fr equency) plasma treatment and hydrogen passivation using microwave ind uced remote plasma treatment. By combining the oxide surface passivati on and hydrogen passivation by remote plasma from the front side and b y rf plasma from the back side, a significant improvement in short-cir cuit 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 r eported on EMC multicrystalline silicon.