Construction of thin strain-relaxed SiGe layers and method for fabricating the same

A fabricating method of a thin strain-relaxed SiGe layers, comprising steps of:

• providing an semiconductor substrate;
• forming a buffer layer on the semiconductor substrate, the buffer layer including Si and Ge;
• forming a Si(C) layer on the buffer layer, the buffer layer providing an in-plane lattice match between the buffer layer and the Si(C) layer, serving as a trapping center for misfit dislocations and suppressing the propagation of threading dislocations;
• forming an epitaxial layer on the Si(C) layer, the epitaxial layer including Si and Ge, the Ge content in the buffer layer and the epitaxial layer being the same, the thickness of the epitaxial layer being thicker than the buffer layer, and the lattice constant of the Si(C) layer being smaller than that of the buffer layer and epitaxial layer;
• and
• annealing the epitaxial layer.