Semiconductor Device and Method

A method comprising:

• forming a fin extending from a substrate, the fin having a lower portion comprising silicon, the fin having an upper portion comprising silicon germanium;
• simultaneously removing silicon and germanium from sides and a top surface of the fin, the silicon removed at a first rate, the germanium removed at a second rate, the second rate being less than the first rate;
• and
• forming a source region and a drain region in the fin.

A device comprising:

• a substrate;
• a first semiconductor layer extending from the substrate, the first semiconductor layer comprising silicon;
• a second semiconductor layer on the first semiconductor layer, the second semiconductor layer comprising silicon germanium, edge portions of the second semiconductor layer having a first germanium concentration, a center portion of the second semiconductor layer having a second germanium concentration, the second germanium concentration being less than the first germanium concentration, the edge portions of the second semiconductor layer comprising sides and a top surface of the second semiconductor layer;
• a gate stack on the second semiconductor layer;
• lightly doped source/drain regions in the second semiconductor layer, the lightly doped source/drain regions being adjacent the gate stack;
• and
• source and drain regions extending into the lightly doped source/drain regions.