Silicon-on-insulator substrates having selectively formed strained and relaxed device regions

A semiconductor device substrate, comprising:

• a bulk layer;
• an oxide layer formed on the bulk layer;
• a donor wafer comprising a plurality of regions of relaxed SiGe layer, and a plurality of regions of relaxed silicon layer, formed by epitaxially growing a graded silicon germanium (SiGe) buffer layer directly on a silicon substrate and a relaxed SiGe layer directly on the graded SiGe buffer layer;
• forming a patterned hardmask directly on the relaxed SiGe layer;
• removing selective portions of the graded SiGe buffer layer and the relaxed SiGe layer;
• epitaxially growing the plurality of regions of relaxed silicon layer directly on the silicon substrate, corresponding to the removed selective portions of the graded SiGe buffer layer and the relaxed SiGe layer;
• and removing the hardmask layer;
• and a silicon device layer comprising a plurality of regions of tensile strained silicon layer on the plurality of regions of relaxed SiGe layer of the donor wafer, and a plurality of regions of additional relaxed silicon layer on the plurality of regions of relaxed silicon layer of the donor wafer, formed by:
• epitaxially growing the silicon device layer directly on the surface of the donor wafer;
• and transferring the silicon device layer from the donor wafer to a handle wafer comprising a bulk substrate and an insulator layer, so as to form a silicon-on-insulator (SOI) substrate with the silicon device layer maintaining the plurality of regions of tensile strained silicon and the plurality of regions of relaxed silicon.