| 摘要 |
PROBLEM TO BE SOLVED: To reduce the crystal defect of an SIMOX substrate by injecting a specific amount of oxygen ion to an Si substrate, then performing a low- temperature heat treatment under specific conditions, and then performing a high-temperature treatment under specific conditions. SOLUTION: An oxygen ion with a dosage of 3×10<17> /cm<3> or less is implanted to an Si substrate 10 and then the Si substrate 10 is subjected to a low- temperature heat treatment, for example, at 1,250 deg.C or less, at least for 40 minutes, for example, at 1,250 deg.C for one hour in nitrogen atmosphere. At this stage, a high-density oxide island deposition nucleus 20 is formed. Then, high- temperature heat treatment is performed in Ar atmosphere containing, for example, 0.5% oxygen at 1,300 deg.C or higher, for example 1,350 deg.C for five hours, thus forming a continuous oxide film 40. In this case, a high-density oxide island deposition nucleus is generated due to a low-temperature heat treatment and oxide islands, where oxygen gathers due to a high-temperature heat treatment and grows, are incorporated one another and become a continuous oxide film 40.
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