Apparatus for semiconductor device structures and related fabrication methods are provided. A method for fabricating a semiconductor device structure on an isolated region of semiconductor material comprises forming a plurality of gate structures overlying the isolated region of semiconductor material and masking edge portions of the isolated region of semiconductor material. While the edge portions are masked, the fabrication method continues by forming recesses between gate structures of the plurality of gate structures and forming stressor regions in the recesses. The method continues by unmasking the edge portions and implanting ions of a conductivity-determining impurity type into the stressor regions and the edge portions.