Low‐Temperature Surface Passivation of Silicon for Solar Cells

Low‐temperature‐deposited silicon nitride and aluminum oxide films are investigated for reducing carrier recombination at the silicon surface. The insulator/silicon interface properties (fixed charge density, fast interface state density, and surface recombination velocity) are studied as a function of deposition and annealing temperature in the range of 270°–550°C. The effects of UV irradiation and their elimination by charge‐induced passivation are extensively discussed. The successful application of both films for front surface passivation of a novel thin‐silicon solar cell of the back collection type (BACK‐MIS cell) is demonstrated. Finally, a simple configuration for efficient back surface passivation of solar cells is introduced as a possible substitute for the conventional back surface field.