Formation of high-k gate dielectric layers for MOS devices fabricated on strained lattice semiconductor substrates with minimized stress relaxation

摘要

A semiconductor device is formed by providing a semiconductor substrate comprising a strained lattice semiconductor layer at an upper surface thereof and having a pre-selected amount of lattice therein, forming a thin buffer/interfacial layer of a low-k dielectric material on the upper surface of the semiconductor substrate, and forming a layer of a high-k dielectric material on the thin buffer/interfacial layer of a low-k dielectric material. Embodiments include forming the thin buffer/interfacial layer and high-k layer at a minimum temperature sufficient to effect formation of the respective dielectric layer without incurring, or at least minimizing, strain relaxation of the strained lattice semiconductor layer.