Semiconductor device having fin-type field effect transistor and method of manufacturing the same

A semiconductor device, comprising:

• a substrate having a first region and a second region;
• a first MOS transistor including a first fin structure and a first gate electrode in the first region, the first fin structure having a first buffer pattern, a second buffer pattern, and a first channel pattern which are sequentially stacked on the substrate;
• and
• a second MOS transistor including a second fin structure and a second gate electrode in the second region, the second fin structure having a third buffer pattern and a second channel pattern which are sequentially stacked on the substrate,
• wherein the first and second channel patterns comprise a semiconductor material including germanium (Ge), and
• wherein a difference of lattice constants between the first channel pattern and an upper portion of the second buffer pattern is less than a difference of lattice constants between the second channel pattern and an upper portion of the third buffer pattern.

A semiconductor device, comprising:

• a substrate including first and second side-by-side regions;
• and
• first and second metal-oxide-semiconductor (MOS) transistors comprising first and second fin structures on the first and second regions of the substrate, respectively, wherein:
• the first fin structure comprises a first buffer pattern, a second buffer pattern comprising a different lattice constant than the first buffer pattern, and a first channel pattern sequentially stacked on the first region;
• the second fin structure comprises a third buffer pattern comprising a different lattice constant than the second buffer pattern, and a second channel pattern sequentially stacked on the second region;
• and
• the first and second channel patterns and the first, second and third buffer patterns comprise a same semiconductor material.