High Throughput Boron Emitter Formation from Pre-deposited APCVD BSG Layers for TOPCon Solar Cells

This work presents an alternative boron diffusion approach for tunnel oxide passivated contact TOPCon solar cells enabling a highly increased throughput compared to the typically used $\mathbf{BBr_{3}}$ diffusion. We use APCVD BSG layers as the boron dopant source and combine them with a subsequent thermal anneal for dopant drive-in in a quartz tube furnace. Here, we use either a conventional single slot quartz boat configuration, or, for highly increased throughput, a vertical wafer stack configuration with the wafer surfaces in direct contact to each other. We investigate the emitter dark saturation current densities $\boldsymbol{j}_{\boldsymbol{0}\mathbf{e}}$ as well as the energy conversion efficiency of TOPCon solar cells fabricated for each configuration and compare the results to those of a $\mathbf{BBr_{3}}$ reference process.