Method for Manufacturing Simox Substrate and Simox Substrate Obtained by this Method

摘要

Heavy metal contamination in a device process can be efficiently trapped in a substrate.;The present invention comprises: a step of implanting oxygen ions into a wafer; a step of performing a first heat treatment to the wafer in a predetermined gas atmosphere at 1300 to 1390° C. to form a buried oxide layer and also form an SOI layer on a wafer front surface, the wafer before the oxygen ion implantation having an oxygen concentration of 8×10¹⁷ to 1.8×10¹⁸ atoms/cm³ (old ASTM), the buried oxide layer being formed over the entire wafer surface, the present invention being characterized by including: a step of performing a second heat treatment to the wafer subjected to the first heat treatment in a predetermined gas atmosphere at 400 to 900° C. for 1 to 96 hours to form oxide precipitate nuclei in a bulk layer below a defect aggregate layer formed immediately below the buried oxide layer; and a step of performing a third heat treatment to the wafer subjected to the second heat treatment in a predetermined gas atmosphere at 900 to 1250° C. higher than the second heat treatment temperature for 1 to 96 hours to grow the formed oxide precipitate nuclei into oxide precipitates.