Methods for forming structures that include forming a heteroepitaxial layer on a substrate are disclosed. The presently disclosed methods comprise epitaxially forming a buffer layer on the substrate. The substrate has a substrate composition. The buffer layer has a buffer layer composition. The buffer layer composition is substantially identical to the substrate composition. The presently disclosed methods further comprise epitaxially forming a heteroepitaxial layer on the buffer layer. The heteroepitaxial layer has a heteroepitaxial layer composition which is different from the substrate composition.

A semimetal liner and a metal-insulator-metal (MIM) capacitor (MIMCAP) are described along with the methods of manufacture or fabrication. The MIM capacitor structure includes a liner formed of a thin layer or film of a semimetal, which is a few nanometers thick, e.g., a thickness in the range of about 0.5 nm to about 5 nm or more. The semimetal liner is sandwiched between an electrode layer and a dielectric layer, e.g., a layer of high or ultra-high-k material, thereby providing a cap for the electrode to limit leakage currents in the structure.