A CMOS structure includes a first device located using a first active region within a semiconductor substrate, where the first active region is planar and has a first crystallographic orientation. The CMOS structure also includes a second device that is located using a second active region within the semiconductor substrate, where the second active region is topographic and has a second crystallographic orientation absent the first crystallographic orientation. The first crystallographic orientation and the second crystallographic orientation allow for performance optimizations of the first device and the second device, typically with respect to charge carrier mobility. The topographic second active region may also have a single thickness. The CMOS structure may be fabricated using a crystallographically specific etchant for forming the topographic second active region.