Semiconductor device structure and methods of forming the same

A semiconductor device structure, comprising:

• a first source/drain epitaxial layer disposed over a conductive feature;
• a second source/drain epitaxial layer disposed a dielectric material;
• a plurality of semiconductor layers disposed between the first and second source/drain epitaxial layers;
• and
• a gate electrode layer disposed between the first and second source/drain epitaxial layers, wherein the gate electrode layer surrounds the plurality of semiconductor layers, the gate electrode layer comprises a first portion disposed adjacent the first source/drain epitaxial layer and a second portion disposed adjacent the second source/drain epitaxial layer, the first portion has a first bottom surface, the second portion has a second bottom surface, and the first and second bottom surfaces are located at different levels.

A semiconductor device structure, comprising:

• a first conductive feature;
• a first silicide layer disposed on the first conductive feature;
• a source/drain epitaxial feature disposed on the first silicide layer;
• a second silicide layer disposed on the source/drain epitaxial feature;
• a second conductive feature disposed on the second silicide layer;
• a semiconductor layer disposed adjacent the source/drain epitaxial feature;
• a dielectric layer disposed between the first conductive feature and the semiconductor layer wherein the dielectric layer comprises a surface interfacing the first conductive feature;
• and
• a gate electrode layer surrounding the semiconductor layer, wherein the gate electrode layer comprises a surface located above a plane defined by the surface of the dielectric layer.