A COMPARATIVE SECONDARY-ION MASS-SPECTROMETRY TECHNIQUE FOR EVALUATION OF METALLIC IMPURITY ON SILICON SURFACE

To obtain information about metallic contaminations, surface analytica l techniques with an extremely low detection limit for the metal are n ecessary. In this paper, we show by using a comparative secondary ion mass spectrometry technique coupled with total reflection X-ray fluore scence that this contamination can be reduced after optimization of th e cleaning and deoxidation procedures. For chemical treatments, silico n wafers were processes through various cleaning sequences. Control wa fers were used in all experiments before and after processing. For the last operation, a deoxidization time of 90 s and the use of surfactan ts have been found to improve significantly Si surface quality and to minimize Fe and Al concentrations.