Patent ID: 7393735

Claim:
A method for forming a semiconductor layer structure comprising the steps of: implanting p-type dopants into a relaxed Si 1-x Ge x layer, with a Ge concentration, x, and relaxation, r, such that the in-plane lattice constant is 0.8-2.4% larger than that of bulk Si, such that a portion of said relaxed Si 1-x Ge x layer is doped p-type with a concentration ranging between 10 15 and 10 19 cm −3 ; activating said p-type dopants by annealing, an activation temperature ranging between about 600° C. and 1100° C.; and, epitaxially regrowing a multi-layer structure comprising: a bottom Si 1-z Ge z buffer layer on top of said relaxed Si 1-x Ge x layer; a tensile tensile-strained Si quantum well layer on top of said bottom Si 1-z Ge z buffer layer; a top Si 1-m Ge m buffer layer on top of said tensile tensile-strained Si quantum well layer; a Si cap layer on top of said top Si 1-m Ge m buffer layer that is under tensile strain, wherein a portion of said bottom Si 1-z Ge z buffer layer or top Si 1-m Ge m buffer layer or both buffer layers adjacent to said Si quantum well is substantially undoped and a portion or entirety of the remaining regions of said bottom Si 1-z Ge z buffer layer or top Si 1-m Ge m buffer layer or both buffer layers is doped n-type with a concentration ranging between 10 17 cm −3 to 10 21 cm −3 .