Multi-channel devices and methods of manufacture

A method of manufacturing a semiconductor device, the method comprising:

• forming a stack of nanostructures and a semiconductor fin over a substrate;
• protecting the semiconductor fin with a protective material;
• performing a first interface treatment on the stack of nanostructures after the protecting the semiconductor fin;
• depositing a first gate dielectric after the performing the first interface treatment, the first gate dielectric being thicker around a first one of the stack of nanostructures than around a second one of the stack of nanostructures;
• removing the protective material after the depositing the first gate dielectric;
• depositing a second gate dielectric after the removing the protective material;
• and
• depositing a gate electrode in physical contact with both the first gate dielectric and the second gate dielectric.

A method of manufacturing a semiconductor device, the method comprising:

• forming a semiconductor fin over a substrate;
• forming a stack of nanostructures over the substrate;
• removing at least a first layer of the stack of nanostructures;
• after the removing the first layer, performing a wire release process on the stack of nanostructures to form at least a first nanostructure overlying a second nanostructure;
• treating the first nanostructure and the second nanostructure;
• depositing a first gate dielectric on the first nanostructure and a second gate dielectric on the second nanostructure, the first gate dielectric having a larger thickness than the second gate dielectric;
• after the depositing the first gate dielectric, depositing a third gate dielectric on the semiconductor fin;
• and
• depositing a gate electrode over the first gate dielectric, the second gate dielectric, and the third gate dielectric.