Patent ID: 7501329

Claim:
A method comprising: gettering a device region in a semiconductor wafer, wherein: gettering includes forming a relaxed silicon germanium region to be proximate to the device region; forming the relaxed silicon germanium region includes: implanting germanium ions into a silicon substrate using at least a first doping profile and a second doping profile, the first doping profile to implant germanium ions with a desired dose and energy to provide a first concentration of germanium ions at a first depth in the silicon substrate, the second doping profile to provide a second concentration of germanium ions at a second depth in the silicon substrate, wherein the first depth in the silicon substrate is lower than the second depth and the first concentration is lower than the second concentration; and annealing to transform the silicon substrate with the first and second concentrations of germanium ions into the relaxed silicon germanium region, wherein the relaxed silicon germanium region has a graded germanium content, wherein the relaxed silicon germanium region generates defects to getter impurities from the device region.