Material properties of polysilicon layers deposited by atmospheric pressure iodine vapor transport

Fast (3 /spl mu/m/min) and direct deposition of large-grain (/spl sim/20 /spl mu/m) polycrystalline silicon layers on foreign substrates at intermediate temperatures (/spl sim/900/spl deg/C) is achieved by an atmospheric pressure iodine vapor transport technique. A hole Hall mobility of 51 cm/sup 2//V.s at a doping density of 5.5/spl times/10/sup 17/ cm/sup -3/ was measured in an as-deposited material. After hydrogen passivation, it increased to 76 cm/sup 2//V.s. Crystallographic defects mostly consist of less detrimental stacking faults and twins, with a few dislocations. Diagnostic PV devices using an N/sup +/-a-Si/i-a-Si/APIVT-Si(absorber)/P/sup +/-CZ-Si structure demonstrated an open-circuit voltage of 0.48 V and 0.58 V at one and 13 suns, respectively. Highly [110]-oriented silicon layers were attained.