N-type Czochralski silicon ingots - Oxygen-related defects in the last solid fraction

Abstract

The focus of this master's thesis has been the formation of oxygen-related defects in the last 10 cm before the tail in Czochralski silicon ingots for solar cell applications. For nine industrial standard ingots from standard and recharged processes, lifetimes and impurity concentrations have been mapped in order to compare axial and radial trends in these to information about their thermal histories. These investigations have been performed for material samples in as grown conditions and after precipitation annealing for the visualization of as-grown defects. Lastly, simplified computer simulations have been conducted and compared to the experimental results. For samples with low cooling rates, the rate of defects formation and lifetime variations seem to depend on oxygen and carbon concentrations.