Thermal treatment for gate dielectrics

Abstract

Embodiments described in this disclosure relate to formation of a gate structure of a device, such as in a replacement gate process, and the device formed thereby. In some examples, after an interfacial layer and a gate dielectric layer are deposited, a rapid anneal process, such as laser anneal or flash lamp anneal process, is performed in a controlled ambient nitrogen-containing environment to form a nitrided portion in the gate dielectric layer. The nitrided portion passivates the defects at the surface of the gate dielectric layer and can serve as a barrier to prevent etchant chemistry and defects/dopants from the subsequent gate stack layers from affecting or diffusing through the gate dielectric layer. Particularly, the rapid anneal process is performed on a millisecond scale to confine nitrogen atoms in the gate dielectric layer without diffusing into the underlying interfacial dielectric and/or any neighboring structure such as fin.