| 摘要 |
PURPOSE:To form a getter site selectively in an arbitrary region in a single crystal silicon layer by an economical process by a method wherein a polycrystalline silicon layer in direct contact with a specified region only is formed. CONSTITUTION:An N<+> type buried region 2 is formed in a P-type silicon substrate 1; an N-type silicon layer 3 is epitaxially grown on the region 2; a thermal oxide film 4 is further formed; openings are made in supposed forming part of an isolation diffused region; undoped polycrystalline silicon layers 5, 5' are formed on the surface and backside of a wafer by LPCVD process; and the polycrystalline silicon layer 5 is implanted with ion. Next, an SiO2 film 7 is deposited by CVD process to be heat-treated forming a P<+> type isolation diffused region 8 reaching the P-type substrate 1 and after removing the SiO2 film 7, the region 8 is thermal-oxidized to convert overall polycrystalline silicon layers 5, 5' to oxide films 9, 9'. At this time, an interface is formed into single crystal silicon layers 1, 3 on the part of a polycrystalline silicon layer and a single crystal silicon layer in direct contact with each other.
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