Measurement, modelling and simulation of defects in as-grown Czochralski silicon

• Published in: Journal of crystal growth 1997-10, Vol.180 (3-4), p.353-362
• Main Authors: Vanhellemont, J., Senkader, S., Kissinger, G., Higgs, V., Trauwaert, M.-A., Gräf, D., Lambert, U., Wagner, P.
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Critical radius; Cross-disciplinary physics: materials science; rheology; Cz silicon; Defects and impurities in crystals; microstructure; Exact sciences and technology; Grown-in defects; Growth from melts; zone melting and refining; LST; Materials science; Methods of crystal growth; physics of crystal growth; Microscopic defects (voids, inclusions, etc.); Nucleation; Physics; Structure of solids and liquids; crystallography; Voids
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/S0022-0248(97)00233-9

Defects in as-grown and heat-treated 150 and 200 mm Czochralski silicon crystals are investigated for different crystal pulling conditions and thermal treatments. First results are presented using noncontact carrier recombination imaging for detection of electrically active defects. The defect densities and sizes are compared with the results of computer modelling, suggesting that the observed defects in as-grown material are most likely large voids, possibly partially filled with silicon oxide. In contrast, the defects observed after prolonged heat treatments are silicon oxide precipitates with a density which is several orders of magnitude larger. The voids nucleate at temperatures above 1100°C by a homogeneous nucleation process and grow further to the observed size during further cooling of the crystal. They are responsible for the midfield breakdown of 10–50 nm gate oxides.