| 摘要 |
A high-resistance substrate with good RF characteristics, which has an interstitial oxygen concentration ([Oi]) of 8E17 cm-3 or less, an oxygen precipitate density ([BMD]) of 1E8 cm-3 or more, and a substrate resistivity of 500 OMEGA.cm or more is used. A heat-treating step of the device process is performed for 25 hrs or less as a value calculated assuming that the temperature is 1,000° C. This suppresses a decrease in the resistance of the substrate, prevents crystal defects such as slip, and improves the yield.
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