| 摘要 |
PROBLEM TO BE SOLVED: To prevent external diffusion in drive-in diffusion of impurities added for isolation region formation of a P-N junction. SOLUTION: Boron ion 5 is implanted selectively to a region for isolation region formation via a thermal silicon oxide film on a P-type semiconductor substrate 1, boron 6 is added to an epitaxial layer 2, a silicon oxide film 10 of a low temperature is formed on the semiconductor substrate 1, and an isolation region 8 is formed by drive-in diffusion. External diffusion of the boron 6, which is additive impurity from an isolation region, is restrained.
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