Effect of Grown-In Defects on the Structure of Oxygen Precipitates in Cz-Si Crystals with Different Diameter
IR-spectroscopy with computer analysis of the shape of the Si-O absorption band, electron microscopy, X-rays diffraction and measurements of unsteady photoconductivity timedecay under band-to band excitation were used to investigate the influence of defects in different diameter (40 – 300 mm) Si ingots on the oxygen precipitation due to two-stage annealing (750 оС + 1050 оС). It is shown that large size Cz-Si ingots have a relatively low concentration of electrically active micro-defects, containing small (0.06 – 0.1 μm) dislocation loops. During thermal treatments this leads to the formation of a low stressed oxide phase (SiO2) with an enhanced thermo-stability. The precipitates in small size ingots, however, contain distorted 4-fold rings of SiO4 tetrahedra.
A. Cavallini, H. Richter, M. Kittler and S. Pizzini
V.G. Litovchenko et al., "Effect of Grown-In Defects on the Structure of Oxygen Precipitates in Cz-Si Crystals with Different Diameter", Solid State Phenomena, Vols. 131-133, pp. 405-412, 2008