Patent ID: 6878610

Claim:
A method of fabricating several crystalline layers on a crystalline substrate, comprising the steps of: growing a first crystalline layer of a first natural crystal lattice constant that is different from the lattice constant of said crystalline substrate, on said crystalline substrate; growing a second crystalline layer of a second natural constant that is different from the natural constant of said first crystalline layer, on said first crystalline layer; and growing a third low defect density crystalline layer of a third natural constant that is different from the natural constant of said second crystalline layer, on said second crystalline layer, so as to promote the creation of defects into at least said second crystalline layer, wherein the growth of an initial portion of said third low defect density crystalline layer results in a strained layer however becoming a relaxed layer during the growth of a final portion of said third low defect density crystalline layer, with the relaxation of said third low defect density crystalline layer resulting in defects and dislocations induced in said underlying, second crystalline layer.