Microdefects distribution in Czochralski-grown silicon crystals

Striated microdefect distribution (swirl defects) are formed by the heat treatment in Czochralski-grown silicon crystals. The striation observed by etching has two period components 1–2 mm and 300–500 μm along growth direction. The corresponding microdistribution of oxygen was examined by the scanning infrared absorption method with the collimated beam of 100 μm in diameter. The results show that the distribution with the period of 1–2 mm was only observed, but not the microdistribution with the period of 300–500 μm. It is proposed from the results that microdefects are originated at a high oxygen-concentration region from the nuclei which were introduced in a striated pattern with the period of 300–500 μm during crystal growth. The nucleus is not interstitial oxygen itself.