Silicon nitride layers for DopLa-IBC solar cells

Abstract

In this work, we report on the development of silicon nitride (SiNx) 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 SiNx layers on both the rear and front surface. Focusing on the rear surface, we have determined a SiNx 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 SiNx films more transparent than their SiCx 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/cm2 is expected.