Stress-Induced Nitrogen and Oxygen Segregation and Complexing Investigated by High Resolution Synchrotron FTIR

Nitrogen doped Czochralski (N-CZ) and Float Zone (N-FZ) silicon were measured by high resolution synchrotron Fourier Transform IR spectroscopy (HR-FTIR). The chemical complexes were analyzed in specific regions with known extended defects, i.e., denuded or precipitated regions of annealed N-CZ Si wafers, in N-FZ Si with ring defects and on “N-Skin” region. The absorption lines were assigned to chemical complexes previously studied by first principles calculations. In annealed N-CZ Si wafers, a strong correlation was observed between the absorption line intensity depth variations and the defect distributions revealed by an Oxygen Precipitate Profiler (OPP), and oxygen and nitrogen SIMS profiles. Transformation of chemical complexes from one type to another was observed. A defect band, visible as an OPP peak at the denuded zone-bulk interface was found to be related to vacancy defect enhancement of oxygen precipitation via production of mobile N2. For the as grown N-FZ, the radial dependency of IR absorption line intensity is correlated to x-ray topography contrast.