A semiconductor device is provided. The semiconductor device includes a bottom epitaxial layer, a gate stack formed over the bottom epitaxial layer, the gate stack including a work function metal (WFM) layer, a channel fin formed on the bottom epitaxial layer, a first interlayer dielectric (ILD) layer formed in a gate landing area over the gate stack, a second ILD layer formed in an area other than the gate landing area, and a WFM encapsulation layer formed between the first ILD layer and the second ILD layer, and formed on sidewalls of the gate stack.