Iron precipitation in float zone grown silicon

Temperature dependent iron precipitation in float zone grown silicon wafers has been experimentally investigated. Results of iron precipitation experiments over a wide thermal process temperature range and time are presented. Precipitation of iron in silicon was analyzed by a quantitative assessment of change in interstitial iron using a surface photovoltage minority carrier lifetime analysis technique. Contamination levels of iron in the range 10(11)-10(13) atoms/cm(3) are investigated. It is concluded that maximum iron precipitation occurs in the temperature range of 500-600 degrees C. Iron precipitation is rapid in this region where more than 90% of the interstitial iron precipitates in a period of 30 min. (C) 1997 American Institute of Physics.