| abstract |
A semiconductor device is disclosed. The semiconductor device includes a substrate, a superlattice, which comprises a plurality of layers of alternating materials over the substrate, each of the plurality of layers corresponding to a threshold voltage, a gate trench that extends into the superlattice to a predetermined one the plurality of layers of the superlattice structure, and a high-k layer on the underside and the sidewall of the trench, the high-k layer contacting an etch stop layer of one of the plurality of layers of alternating materials. A gate is located in the trench on top of the high-k layer. |