Contactless Determination of Emitter Sheet Resistance for Diffused Silicon Wafers

The emitter sheet resistance is one of the essential parameters for silicon solar cells with diffused layers. Conventional measurement methods of emitter sheet resistance either require electrical contacts or are impacted by the bulk resistivity. In this paper, a novel method based on the combination of eddy-current conductance and photoluminescence imaging is developed for a contactless determination of the emitter sheet resistance as well as bulk resistivity. The accuracy of the method is demonstrated by both numerical simulation and experimental validation. The contactless nature of this method makes it an attractive proposition for inline inspection of diffused layers in solar cell manufacturing.