| 摘要 |
PROBLEM TO BE SOLVED: To prevent deterioration of the life time of a carrier resulting from the mixing of heavy metal impurities, by forming a gettering layer for segregating impurities, so as to make an interface with a first main surface on the side opposite to an interface of a second semiconductor layer with a first semiconductor layer. SOLUTION: A damage layer 102 is formed on the lower main surface of a single crystal silicon substrate containing N-type impurities of comparatively low concentration. From the lower main surface side of the silicon substrate, phosphorus ions, e.g. are introduced. By thermally diffusing the implanted phosphorus ions, an N<+> buffer layer 104 is formed. From the lower main surface side of the silicon substrate, boron ions, e.g. are introduced. By thermally diffusing the implanted boron ions, a P<+> collector layer 103 is formed. The upper main surface of the silicon substrate is eliminated by a giver thickness. The residual part of the silicon substrate turns to an N<-> layer 105. An MOS region 10 is formed on the upper main surface side of the N<-> layer 105. A collector electrode 106 is formed on the lower main surface side of the damage layer 102.
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