A non-planar gate all-around device and method of fabrication thereby are described. In one embodiment, a multi-layer stack is formed by selectively depositing the entire epi-stack in an STI trench. The channel layer is grown pseudomorphically over a buffer layer. A cap layer is grown on top of the channel layer. In an embodiment, the height of the STI layer remains higher than the channel layer until the formation of the gate. A gate dielectric layer is formed on and all-around each channel nanowire. A gate electrode is formed on the gate dielectric layer and surrounding the channel nanowire.