| 摘要 |
PROBLEM TO BE SOLVED: To make a semiconductor device equipped with an SOI-MOSFET, hard to be influenced by the stress generated owing to a difference in coefficient of thermal expansion between a buried oxide film, and an SOI film without losing excellent characteristics of small parasitic capacitance and a small S value. SOLUTION: On a semiconductor substrate (21), lower-layer buried oxide films (42), a stress reducing film (43, 53), an upper-layer buried oxide film (44), and the SOI film (25) are formed sequentially and the coefficient of thermal expansion of the stress reducing film (43) is larger than the coefficient of thermal expansion of the upper-layer buried oxide film (44). The stress reducing films (43, 53) are preferably almost equal in coefficient of thermal expansion to or larger than the SOI film, and formed of, for example, a composite film (53) forming by laminating a silicon film, a germanium film arranged thereupon, and a silicon film arranged thereupon. COPYRIGHT: (C)2004,JPO
|
