Method, apparatus, and system having super steep retrograde well with silicon and silicon germanium fins

A method for forming a finFET device, comprising:

• forming an n-doped and a p-doped region in a semiconductor wafer;
• forming a layer of silicon germanium above both the n-doped and p-doped regions;
• removing a portion of the silicon germanium layer above the p-doped region to create a first recess;
• forming a layer of silicon in the first recess;
• etching away at least a portion of the silicon layer and the underlying p-doped region;
• etching away at least a portion of the silicon germanium layer and the underlying n-doped region;
• forming fins of the finFET transistor from the unetched silicon and silicon germanium layers;
• and
• forming a shallow trench isolation dielectric in the etched away portion of the silicon germanium layer and the underlying n-doped region and in the etched away portion of the silicon layer and the underlying p-doped region.

A finFET device, comprising:

• a silicon substrate having an n-doped region and a p-doped region;
• at least one fin comprised of epitaxial silicon and having a first channel above the p-doped region;
• at least one fin comprised of epitaxial silicon germanium and having a second channel above the n-doped region;
• a first channel region in the epitaxial silicon fin having an average p-dopant concentration at least a factor of about 2 lower than an average p-dopant concentration of a region located at about 0 to about 40 nm beneath the first channel region;
• and
• a second channel region in the epitaxial silicon germanium fin having an average n-dopant concentration at least a factor of about 2 lower than an average n-dopant concentration of a region located at about 0 to about 50 nm beneath the second channel region.