Patent ID: 7696000

Claim:
A semiconductor structure comprising a carbon-substituted single crystal silicon layer having a thickness and a defect density less than about 1.0×10 9 /cm 2 located beneath a surface of a semiconductor substrate, wherein said carbon-substituted single crystal silicon layer includes a first volume, a second volume, a third volume, and a fourth volume, wherein said first volume is located within said single crystal silicon layer between said surface of said semiconductor substrate and a 2% line corresponding to a distance of 2% of said thickness away from said surface; said third volume is located within said single crystal silicon layer between said 2% line and a 30% line corresponding to a distance of 30% of said thickness away from said surface; and said second volume is located within said single crystal silicon layer between said 30% line and a 60% line corresponding to a distance of 60% of said thickness away from said surface; said fourth volume is located within said single crystal silicon layer between said 60% line and a bottom surface of said carbon-substituted single crystal silicon layer; and wherein the average concentration of carbon in said first volume is equal to or less than 25% of the average concentration of carbon in said second volume, said average concentration of carbon in said second volume is equal to or greater than 0.8% in atomic concentration, and the concentration of carbon monotonically decreases from the depth at 30% of said thickness of said carbon-substituted single silicon layer to the depth at 2% of said thickness of said carbon-substituted single silicon layer.