OBSERVATION OF ENHANCED HYDROGEN DIFFUSION IN SOLAR-CELL SILICON

We report the observation of higher diffusivity of hydrogen in some solar cell silicon compared to that in Czochralski and float zone wafers. SIMS profiles of hydrogen/deuterium, implanted at low energies and in a temperature range of 100-300-degrees-C, are compared for a variety of different types of silicon substrates. In addition, a new technique that utilizes hydrogen decoration of dislocations was applied to directly verify long diffusion depths in some solar cell silicon. Higher diffusivity of hydrogen permits backside hydrogenation of solar cells to be carried out in less than 30 min with a significant improvement in the cell performance.