Investigation of Czochralski silicon grown with different interstitial oxygen concentrations and point defect populations

Czochralski silicon crystals, grown with different interstitial oxygen conc entrations (group I) or different types of intrinsic defects (group II), we re analyzed by X-ray section topography, diffuse X-ray scattering, surface photovoltage, microwave photoconductive decay, and Fourier infrared spectro scopy. The samples of group I showed that the main factor influencing the X -ray section topography images is the amount of precipitated oxygen. The in crease in this amount involves a decrease in size and an increase in densit y of the oxygen precipitates. A strong reduction in the minority carrier di ffusion length is observed after precipitation. These effects seem to be de pendent on the positions along the ingot axis at which the samples were tak en, which would indicate the influence of the sample thermal history on the detectability of oxygen precipitates by means of these techniques. The sam ples of group II are characterized by vacancy-rich, interstitial-rich, and defect-free regions. After copper decoration, the different defects were ob served to have different sizes, densities, shapes, and depth distributions. This feature allows one to clearly distinguish between crystal zones where vacancy or interstitial clusters prevail and where defects are absent. Min ority carrier lifetime values are directly related to the defect volume den sities. The combined use of different characterization techniques proved it self a powerful tool to study different defect types in Czochralski silicon . (C) 2001 The Electrochemical Society.