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The physical properties of point defects in Si crystal have not been established with certainty. That makes it difficult to calculate the behavior of grown in defects in CZ Si crystal growth. With high precision thermal analysis we studied the physical properties of point defects from which the grown in defects distribution could be calculated. In this study we focused the attention on the V I boundary in which the vacancy and self interstitial concentrations are balanced, which appears in case of slowly decreasing the crystal growth rate. we assumed that the determination of the physical properties was an optimization problem, and we applied a genetic algorithm method and a simulated annealing method. In addition, we examined the optimized physical properties with physical considerations and reproducibility of V I boundary shape in calculation. As a result, we estimated one promising set of the physical properties, which were used to calculate the grown in defect distribution. The calculation result showed that (1) it could reproduce the experimental results and (2) the concentration difference (DC ) between vacancy and self interstitial was related to grown in defect types.

The behavior of point defects was visualized in lightly and heavily boron (B)-doped Czochralski-silicon (CZ-Si) crystals by employing a special growth technique, namely, rapidly cooling a growing crystal after it is detached from the Si melt. In the case of crystal growth with a high pulling rate, an anomalous oxygen precipitation (AOP) region dominated by vacancies appeared, whereas in the case of crystal growth with a low pulling rate, a dislocation loop region dominated by self-interstitials appeared. In the crystals cooled rapidly after halting growth for several hours, self-interstitials flowed into the AOP region and dislocation loop regions formed and expanded, while the AOP region shrunk due to diffusion of excess vacancies to the crystal surface and void regions. These transient changes in the point defect distribution were reproduced using a point defect simulator. Defect regions related to self-interstitials could not be confirmed in the heavily B-doped crystals with resistivities of 10 mΩcm or less, where the void- and oxidation-induced stacking fault (OSF)-ring regions disappeared completely at the center of the crystal. These results show that the behaviors of point defects in heavily doped CZ-Si crystals with various impurities are important research subjects in relation to future advanced power applications.

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By means of first principles calculation we studied the interfacial energy of void defects which were formed during the crystal cooling process in a Czochralski(CZ) puller. In this study the interfacial structure of void defect was assumed to be either a vacuum/oxide film/Si(111) structure or a vacuum/Si(111) structure. The calculation result showed that the interfacial energy was 0.886 Jm -2 in the case with an oxide film. It was close to the value(0.830 Jm -2 ) which was derived from the viewpoint of void defects formation around 1373 K. And it was 1.551 Jm -2 in the case without an oxide film, which was twice as large than an interface with an oxide film. For the range of Si crystal growth conditions for semiconductor use, we calculated the size and density of void defects with the interfacial energy which was obtained from first principles calculation in the case with an oxide film. The results agreed with the experimental results.