Micro Defect Size in Si Single Crystal Grown by Czochralski Method

Abstract

Single crystals for 300 mm wafer are grown by horizontal magnetic Czochralski method. 300 mm wafers are made from the vertical samples cut from crystal along ingot axial direction. Micro defects in various defect regions are investigated with various measurement methods. In order to investigate the size of the defects, the locations of defects are identified, the wafers with the defects are cut in cross-sectional direction, and the sizes of the defects are measured by transmission electron microscopy (TEM). The voids more than 20 nm size exist in vacancy-rich region. Any as-grown defect is not observed by any available measurement tools in the region having nuclei of oxidation-induced stacking fault (P-band), pure silicon in a vacancy-dominant crystal region (Pv), and pure silicon in an interstitial-silicon-dominant crystal region (Pi). High sensitive laser scattering tomography system with the detection limit of 20 nm size is used to investigate as-grown defects in P-band, Pi, and Pv regions. It is concluded that there are no as-grown defects more than 20 nm size in P-band, Pi, and Pv regions.

Correlation between Copper Precipitation and Grown-In Oxygen Precipitates in 300~mm Czochralski Silicon Wafer

“…3. Results and discussion Figure 2 shows the OM images of Cu precipitates in the specimens S15 taken along the radial direction of the 300 mm CZ silicon wafer.…”

“…Generally, the grown-in oxygen precipitates are too small to be observed by the common light-scattering and etching techniques. Even for transmission electron microscopy (TEM), it is generally appropriate for revealing the grown-in defects in size larger than 20 nm [3].…”

Impact of Rapid Thermal Oxidation at Ultrahigh-Temperatures on Oxygen Precipitation Behavior in Czochralski-Silicon Crystals II

“…Thus, both local and widespread nonuniformity often exists in the grown crystal. 9,10 To address this very important problem, we have proposed rapid thermal oxidation (RTO) at ultrahigh temperature (ultrahigh-temperature RTO).11 Our results obviously demonstrated that the oxygen precipitates generated during the crystal growth were dissipated entirely, and dense oxygen precipitate nuclei were formed uniformly in the radial direction during RTO at temperatures over 1350• C. We believed that the newly formed oxygen precipitates in the wafers that had been subjected to ultrahigh-temperature RTO were closely related to preserved vacancies. In particular, each oxygen precipitate nucleus is thought to consist of an oxygen-vacancy complex (for example, O 2 V).…”

“…Thus, both local and widespread nonuniformity often exists in the grown crystal. 9,10 To address this very important problem, we have proposed rapid thermal oxidation (RTO) at ultrahigh temperature (ultrahigh-temperature RTO).…”

“…Thus, both local and widespread nonuniformity often exists in the grown crystal. 9,10 To address this very important problem, we have proposed rapid thermal oxidation (RTO) at ultrahigh temperature (ultrahigh-temperature RTO). 11 Our results obviously demonstrated that the oxygen precipitates generated during the crystal growth were dissipated entirely, and dense oxygen precipitate nuclei were formed uniformly in the radial direction during RTO at temperatures over 1350…”