Comprehensive Model for Charge Carrier Recombination in Czochralski-Grown Silicon Due to Oxygen Precipitation in Industrial Solar Cell Manufacturing

Oxygen precipitates are among the most detrimental oxygen-related silicon bulk defects formed during solar cell manufacturing. These defects are formed only during high-temperature processes, impeding an identification of prone materials during incoming inspection. Moreover, the prediction of oxygen-precipitate-related bulk charge carrier recombination currently requires advanced numerical simulation. This work presents an easily implementable model to predict the bulk carrier lifetime limit, using the temperature-time profile of a high-temperature process as well as the material properties as the input data. In addition to published analytical descriptions of oxygen precipitation, an empirical description of the retarded growth of small precipitates is included. Furthermore, the time-lag in nucleation is explicitly considered, which is, to our knowledge, not implemented in oxygen precipitation modeling so far. The calibration of the two free parameters of the model is achieved using the experimental data of 19 different thermal process combinations performed using a single material. This results in a good agreement not only for the material used for calibration but also for other silicon materials. A validation based on passivated emitter and rear cells as well as on test structures confirms the ability of the model to predict bulk carrier lifetimes after solar cell processing.