Specification of solar cell emitter characteristics using noncontact dopant concentration and minority carrier lifetime measurement

摘要

A method and apparatus are provided for estimating the effect of wafer property changes on operating parameters of a photovoltaic cell during fabrication. While the wafer is being photovoltaically produced, measurements of the emitter sheet resistance, minority carrier lifetime and wafer resistivity of the wafer are obtained. Measurements can be made in-line with manufacturing. The current and voltage (IV) parameters of the photovoltaic cell, such as V _OC , I _SC and charge rate, are estimated based on some of the obtained measurements. Calculation routines for the IV parameters can be monitored for accuracy and updated based on actual observations of the IV parameters as measured in the final photovoltaic cell. The update may be based on a comparison of the imputed wafer characteristics generated based on the observed wafer characteristics and the observed values of the IV parameters. Measurements and IV parameters can be used to identify process defects.