Catalytic phosphorus and boron doping of amorphous silicon films for application to silicon heterojunction solar cells

We investigate a novel doping method, catalytic impurity doping (Cat-doping), for application to the fabrication of silicon heterojunction(SHJ) solar cells. Thin n-or p-type doped layers can be formed on intrinsic amorphous Si (a-Si) films by exposing P-or B-related radicals generated by the catalytic cracking of phosphine (PH3) or diborane (B2H6) gas molecules. The passivation quality of underlying a-Si films can be maintained both for phosphorus (P) and boron (B) Cat-doping if we carefully choose the appropriate substrate temperature during Cat-doping. We confirm the rectifying and photovoltaic properties of an SHJ solar cell containing a B Cat-doped layer as a p-type a-Si emitter. These findings suggest the applicability of Cat-doping to SHJ solar cells. (C) 2017 The Japan Society of Applied Physics