Silicon nitride layers for DopLa-IBC solar cells

In this work, we report on the development of silicon nitride (SiN
_x
) layers to be applied to crystalline silicon high-efficiency solar cells. In particular, our research group has developed the concept of Doped by Laser (DopLa) solar cells where the highly doped regions are based on laser processed dielectric films. This concept has been recently applied to Interdigitated Back-Contacted (IBC) solar cells where some limitations associated to silicon carbide films arisen. The objective is to replace these films by SiN
_x
layers on both the rear and front surface. Focusing on the rear surface, we have determined a SiN
_x
layer that could be etched by conventional wet processes avoiding the plasma etching used in our current devices that degrades their surface passivation. On the other hand, for the front surface we found deposition conditions of SiN
_x
films more transparent than their SiC
_x
counterparts and that could stand the subsequent cleaning procedures included in the solar cell fabrication process. A gain in short-circuit current of 0.1 mA/cm
²
is expected.