SEMICONDUCTOR DEVICE HAVING TIPLESS EPITAXIAL SOURCE/DRAIN REGIONS

A semiconductor device having tipless epitaxial source/drain regions and a method for its formation are described. In an embodiment, the semiconductor device comprises a gate stack on a substrate. The gate stack is comprised of a gate electrode above a gate dielectric layer and is above a channel region in the substrate. The semiconductor device also comprises a pair of source/drain regions in the substrate on either side of the channel region. The pair of source/drain regions is in direct contact with the gate dielectric layer and the lattice constant of the pair of source/drain regions is different than the lattice constant of the channel region. In one embodiment, the semiconductor device is formed by using a dielectric gate stack placeholder.