A determination of the key sources of variation affecting ingot lifetime

The efficacy of ingot level lifetime testing has been limited due to historically poor correlation between ingot lifetime and cell performance. Studies have shown that the DC photoconductance decay is capable of determining differences in average ingot lifetime as a function of starting material, but those studies showed the effects to be a small portion of the total variation. This work looks at a new attempt to correlate ingot lifetimes and cell performance given a more stable starting material supply, and an overall accounting of the sources of variation contributing to ingot lifetime. Finally, ingots whose lifetime was particularly low relative to the predicted performance were studied leading to an indication of additional root causes. The work, as a whole, provides a perspective on the practical impact of various factors on ingot lifetime.