Printed fire-through contacts (FTC) - an alternative approach for local rear contacting of passivated solar cells

The novel fire-through contact (FTC) technology is a drop-in replacement for common local contact technologies such as i-PERC and LFC. Analogous to printed front contacts, the fire-through contact mechanism employs local penetration of the dielectric passivation layer during contact firing. A fire-through metal paste is locally applied onto the rear passivation layer followed by full area printing of a non-fire-through Al paste. Thus, printing technology fully replaces laser processes. In this work, microstructure analysis of the FTC contact formation as well as an analysis of the recombination and contact properties is carried out in order to identify the optimum contact layout. In the second part of the paper, the application of the concept to solar cells is presented.