Tunnel nitride passivated contacts for silicon solar cells formed by catalytic CVD

An ultra-thin silicon nitride (SiNx) layer formed by catalytic chemical vapor deposition (Cat-CVD) is used to replace the Si dioxide (SiO2) layer of a tunnel oxide passivated contact solar cell. The passivation quality of crystalline Si (c-Si) with a stack of the ultra-thin SiNx and n-type hydrogenated amorphous Si (a-Si:H) or microcrystalline Si ( c-Si:H), also formed by Cat-CVD, is significantly improved by annealing at 850 °C, probably due to the formation of a back surface field layer. Cat-CVD SiNx with thicknesses of up to 2.5 nm can have sufficient tunneling conduction. The ultra-thin SiNx having functions of surface passivation and carrier tunneling, and the unification of the formation method for the tunnel SiNx and conductive layers will lead to the realization of tunnel nitride passivated contact solar cells.