Cmos devices having channel regions with a v-shaped trench and hybrid channel orientations, and method for forming the same

A method for forming a semiconductor device, comprising:

• forming a semiconductor substrate comprising first and second device regions that are isolated from each other by an isolation region, wherein the first device region has a planar surface with a first crystalline orientation, and wherein the second device region comprises at least one V-shaped which has interior surfaces with a second, different crystalline orientation;
• forming a first field effect transistor (FET) at the first device region, wherein said first FET comprises a channel that extends along the planar surface of the first device region;
• and
• forming a second, complementary FET at the second device region, wherein said second FET comprises a channel that extends perpendicularly across the at least one V-shaped trench and along the interior surfaces of said at least one V-shaped trench, and wherein a dopant concentration near the top part of the at least one V-shaped trench is different from that near the bottom of the at least one V-shaped trench.