Title :
Gettering effect of aluminium in mc-Si and c-Si wafers and in solar cells
Author :
Porre, Olivier ; Martinuzzi, Santo ; Pasquinelli, Marcel ; Périchaud, Isabelle ; Gay, Nathalie
Author_Institution :
Lab. de Photoelectr. des Semicond., Marseille Univ., France
Abstract :
It is well admitted that the deposition of a thick (⩾1 pm) aluminium layer on a silicon wafer followed by alloying at T⩾850°C is able to improve the minority carrier diffusion length. In the present work it is shown that the Al-Si alloyed region is a gettering site area which produces a segregation induced gettering effect towards metallic impurities like gold or nickel. The aluminium gettering is also able to remove impurities from extended crystallographic defects like dislocation arrays created in sc-Si wafers. The aluminium treatment was used to improve mc-Si wafers like FZ ones. It was found that Al gettering improves the cells made with mc-Si like those made with Cz wafers, for which the conversion efficiency reaches 13% and 14%, respectively, without antireflection coating
Keywords :
carrier lifetime; dislocation arrays; elemental semiconductors; getters; impurities; minority carriers; semiconductor materials; silicon; solar cells; 13 percent; 14 percent; Al-Si; Al-Si alloyed region; Si; aluminium; conversion efficiency; crystalline silicon wafers; dislocation arrays; extended crystallographic defects; gettering effect; gold impurity; metallic impurities; minority carrier diffusion length; multicrystalline silicon wafers; nickel impurity; segregation induced gettering effect; solar cells; thick aluminium layer; Alloying; Aluminum; Annealing; Gettering; Gold; Impurities; Nickel; Photovoltaic cells; Silicon; Temperature;
Conference_Titel :
Photovoltaic Specialists Conference, 1996., Conference Record of the Twenty Fifth IEEE
Conference_Location :
Washington, DC
Print_ISBN :
0-7803-3166-4
DOI :
10.1109/PVSC.1996.564207
