| 摘要 |
PROBLEM TO BE SOLVED: To easily and effectively remove metal impurity included in semiconductor wafer. SOLUTION: An Si<SB>1-x</SB>Ge<SB>x</SB>polycrystal layer 4 is formed on an SOI layer 3 of an SOI wafer formed of a supporting substrate 1, a BOX layer 2, and the SOI layer 3. Impurity in the SOI layer 3 is gettered to the Si<SB>1-x</SB>Ge<SB>x</SB>polycrystal layer 4 by conducting heat treatment to this SOI wafer. After gettering impurity, the Si<SB>1-x</SB>Ge<SB>x</SB>polycrystal layer 4 is removed by the etching process. The Si<SB>1-x</SB>Ge<SB>x</SB>polycrystal layer 4 can be formed with the LPCVD method, and the existing Si process may be used. Moreover, since the Si<SB>1-x</SB>Ge<SB>x</SB>polycrystal layer 4 has higher etching selectivity for Si, this polycrystal layer 4 can be removed from the SOI wafer by the etching process with higher accuracy. COPYRIGHT: (C)2007,JPO&INPIT
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