Self-Aligned Phase Separation for IBC Cells Using PVD Polysilicon

abstract

We introduce an innovative IBC solar cell process leveraging the directional deposition nature of doped polycrystalline silicon (poly-Si) through physical vapor deposition (PVD). This method enables the self-alignment of passivated contacts, effectively separating the polarities. The self-aligned back contact (SABC) cell incorporates n-type and p-type passivated contacts, achieved through interfacial oxide (SiOX) and doped n- and p-type poly-Si layers respectively, arranged in an interdigitated design on the back side. The insulation between the p-type and n-type poly-Si layers requires only a single structuring process of the firstly deposited p-type poly-Si. The subsequent blanket deposition of n-type poly-Si by PVD remains insulated from the p-type poly-Si layer due to the self-alignment properties inherent in our structuring and deposition processes. The SABC target process sequence can be implemented into existing TOPCon manufacturing lines requiring only two additional processing tools.