Bestimmung von parts per billion sauerstoff in silizium durch eichung der IR-absorption bei 77°K

Abstract

For the i.r.-absorption of oxygen in silicon new calibration curves at room temperature and 77°K are determined by means of the vacuum fusion method. The experimental techniques are reported and their sources of error are discussed. The new values for the calculation of the oxygen concentration from the absorption coefficient measured are: 4·9 ± 0·2 ppm A/cm −1 and 1·9 ± 0·1 ppm A/cm −1 at room temperature and 77°K, respectively. These values are lower by a maximum factor of 2·5 than those published in the literature. Thus the minimum detection level for the IR-absorption method at 77°K is lowered to 20 ppb A, so most of the oxygen concentration observed in silicon crystals can be determined.