Optimization of local contact formation on screen-printed Al2O3 passivated solar cells

The passivated emitter and rear solar cells (PERC) have been investigated for industrial application in recent years. For PERC cells, the rear side is passivated by dielectric films, whereby the dielectric films are locally opened for contact formation. In screen-printed PERC cells, however, the local contacts suffer from Kirkendall voids and weak BSF layer intensely. In this paper, the influence of different dot contact geometries on the local contact formation of rear passivated solar cells was investigated. Decreasing the contact pitch or increasing the opening size, the presence of voids decreased drastically. Besides, the quality of BSF layer is improved.