| 摘要 |
PROBLEM TO BE SOLVED: To eliminate defects that the shape of an embedded oxidation region of an SOI wafer has. SOLUTION: A trench is formed in a single-crystal wafer 200 and its internal wall is etched in wet condition to form a cavity 127. After its internal wall is coated with a crystal growth blocking film and a crystal silicon layer 126 is grown on the top surface of the wafer 200, while leaving the cavity 127, a nitride layer 141 is deposited over an oxide layer, the upper part of the cavity is demarcated with a hard mask 142, opened, and thermally oxidized to form an oxide region 127 and a remaining space 128 in the cavity and also form an oxide region 145 even in the opening part. Then polysilicon is deposited over the entire surface of the wafer 200 and the surface is polished to obtain an SOI wafer, having crystal silicon layers 90 and 126 completely inactivated by a continuous buried oxide area 127.
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