CMOS devices with hybrid channel orientations, and methods for fabricating the same using faceted epitaxy

A method for forming a semiconductor device, comprising:

• forming a semiconductor substrate that comprises at least first and second device regions, both of which have substantially planar upper surfaces oriented along one of a first set of equivalent crystal planes;
• selectively masking the first device region;
• growing a protruding semiconductor structure at the second device region, wherein the protruding semiconductor substrate has multiple intercepting surfaces that are oriented along a second, different set of equivalent crystal planes;
• unmasking the first device region;
• and
• forming a static random access memory (SRAM) cell including a first field effect transistor (FET) at the first device region and a second, complementary FET at the second device region, wherein the first FET comprises a channel that extends along the substantially planar upper surface of the first device region, and wherein the second, complementary FET comprises a channel that extends along the multiple intercepting upper surfaces of the protruding semiconductor structure at the second device region, wherein said SRAM cell comprises at least one pull-down FET located at one of the first and second device regions and at least one pull-up FET located at the other of the first and second device regions.