| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method of a semiconductor device capable of forming a back gate electrode suitable for a circuit formed on a semiconductor substrate. SOLUTION: First, a cavity is formed between an Si substrate 1 and an Si layer 5. Then, while the cavity is allowed to remain, SiO<SB>2</SB>films 31a, 31b are formed in the cavity. Then, an a-Si layer is formed on the upper, the entire surface of the Si substrate 1 so that the inside of the cavity section is embedded therewith. Further, the a-Si layer is polycrystallized by first heat treatment, and a poly-Si layer 34 is formed of the a-Si layer. Then, impurities are introduced into a part 34a formed outside the cavity section in the poly-Si layer 34 by an ion implantation method. After that, the impurities are diffused to the poly-Si layer 34b inside the cavity from the poly-Si layer 34a outside the cavity by second heat treatment. COPYRIGHT: (C)2008,JPO&INPIT
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