A method and structure of an embedded stressor in a semiconductor transistor device having a sigma-shaped channel sidewall and a vertical isolation sidewall. The embedded stressor structure is made by a first etch to form a recess in a substrate having a gate and first and second spacers. The second spacers are removed and a second etch creates a step in the recess on a channel sidewall. An anisotropic etch creates facets in the channel sidewall of the recess. Where the facets meet, a vertex is formed. The depth of the vertex is determined by the second etch depth (step depth). The lateral position of the vertex is determined by the thickness of the first spacers. A semiconductor material having a different lattice spacing than the substrate is formed in the recess to achieve the embedded stressor structure.