Analysis of the oxygen impurity atoms beneath the surface of Cz-silicon by CPAA

Charged particle activation analysis (CPAA) is able to analyze light elements such as carbon, nitrogen and oxygen at trace levels in materials. By comparison with other techniques such as Fourier transform infrared spectroscopy (FTIR), the major advantage of the CPAA is its ability to determine the total concentration of impurities (interstitial, substitutional or incorporated in a complex). Errors due to matrix effects and surface contamination are eliminated. However, this technique does not allow analysis in the first micrometers beneath the surface because the chemical etching, required to rid the surface of superficial contaminants, removes this important part of the compounds’ active zone. The aim of this study is to solve this problem and as a result to be able to determine impurities in the vicinity of the surface. An application on oxygen diffusion profiles in Cz-silicon submitted to a rapid thermal annealing (RTA) will be discussed.