| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device and a method for manufacturing it wherein even in a strain SiGe film formed on a semiconductor substrate with high Ge concentration and with critical film thickness or less, high strain relaxation is achieved with penetration/transformation density being reduced, and for a second SiGe film formed on the strain SiGe film unduration thereof is suppressed to permit it to approach more complete relaxation and hereby improve smoothness. SOLUTION: A semiconductor device is adapted such that there are formed on a substrate with its surface comprising silicon a first Si<SB>1-α</SB>Ge<SB>α</SB>film, a first cap film, a second Si<SB>1-β</SB>Ge<SB>β</SB>film (β<α≤1), and a second cap Si film in this order. The first Si<SB>1-α</SB>Ge<SB>α</SB>film is subjected to lattice relaxation, possessing a horizontal lattice constant equivalent to that of the second Si<SB>1-β</SB>Ge<SB>β</SB>film. COPYRIGHT: (C)2003,JPO
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