Patent ID: 6713779
Filing Date: 2004-03-30
Classification: H01L

Abstract:
A semiconductor device comprising:a first lattice-relaxed Si1âˆ’xGex film formed on a first region on an insulating film, wherein a Ge composition x is in a range of 0 to 1; a second lattice-relaxed SiGe film having a Ge composition greater than the first lattice-relaxed Si1âˆ’xGex film, wherein the second lattice-relaxed SiGe film is formed on a second region on the insulating film; a first strain-Si film formed on the first lattice-relaxed Si1âˆ’xGex film; a second strain-Si film formed on the second lattice-relaxed SiGe film; a complete depletion-mode first field-effect transistor including the first strain-Si film as a channel; and a complete depletion-mode second field-effect transistor including the second strain-Si film as a channel, threshold value of the second field-effect transistor is different from threshold value of the first field-effect transistor.