Techniques and mechanisms for imposing stress on a channel region of an NMOS transistor. In an embodiment, a fin structure on a semiconductor substrate includes two source or drain regions of the transistor, wherein a channel region of the transistor is located between the source or drain regions. At least on such source or drain region includes a doped silicon germanium (SiGe) compound, wherein dislocations in the SiGe compound result in the at least one source or drain region exerting a tensile stress on the channel region. In another embodiment, source or drain regions of a transistor each include a SiGe compound which comprises at least 50 wt % germanium.