Title :
Limiting factors of phosphorus external gettering efficiency in multicrystalline silicon
Author :
Périchaud, Isabelle ; Floret, Francis ; Martinuzzi, Santo
Author_Institution :
Lab. de Photoelectricite des Semicond., Marseilles Univ., France
Abstract :
External gettering by phosphorus diffusion is used to improve the minority carrier diffusion lengths Ln in multicrystalline silicon solar cell wafers obtained by different growth techniques. Polix, Silso, Semix and Eurosolare materials were characterized. It is shown that gettering efficiency depends strongly on the origin of the material. For Polix and Eurosolare wafers, the optimal diffusion temperature is around 900°C; Ln increases with diffusion time and tends to saturate, after 8 hours, at about 300 to 500 μm. However the presence of a too large density of defects, or (and) a high concentration of dissolved oxygen atoms (i.e 1018 cm-3 ) limits the external gettering efficiency, probably by an internal gettering of impurities. Competition between external and internal gettering seems to occur
Keywords :
carrier lifetime; elemental semiconductors; getters; minority carriers; phosphorus; semiconductor device testing; semiconductor doping; semiconductor growth; silicon; solar cells; 300 to 500 mum; 8 h; 900 C; Eurosolare; Polix; Semix; Si:P; Silso; defect density; growth techniques; impurities; internal gettering; minority carrier diffusion length; multicrystalline semiconductor; phosphorus external gettering efficiency; solar cell; Atomic measurements; Gettering; Impurities; Iron; Petroleum; Photovoltaic cells; Semiconductor materials; Silicon; Solar power generation; Temperature;
Conference_Titel :
Photovoltaic Specialists Conference, 1993., Conference Record of the Twenty Third IEEE
Conference_Location :
Louisville, KY
Print_ISBN :
0-7803-1220-1
DOI :
10.1109/PVSC.1993.347045
