Semiconductor devices and methods of manufacture

A method comprising:

• forming a multilayer structure over a substrate;
• forming an opening in the multilayer structure and exposing a first layer of the multilayer structure along a sidewall of the opening;
• forming a first source/drain structure adjacent the first layer;
• forming a second source/drain structure over the first source/drain structure, the second source/drain structure comprising a greater percentage by volume germanium than the first source/drain structure, a portion of the second source/drain structure being located between a bottommost portion of the first source/drain structure and the substrate;
• prior to the forming the first source/drain structure, depositing a dielectric material in the opening;
• forming an inner spacer from the dielectric material, the inner spacer being between the first layer and a second layer of the multilayer structure;
• and
• after the forming the first source/drain structure, removing the dielectric material at the bottom of the opening.

A semiconductor device comprising:

• a first multilayer channel over a substrate;
• and
• a source/drain region, wherein the source/drain region comprises:
• a first structure interfacing the first multilayer channel, the first structure comprising a first semiconductor material with a first volume concentration of germanium;
• and
• a second structure interfacing the first structure, the second structure comprising a second semiconductor material with a second volume concentration of germanium, the second volume concentration of germanium being greater than the first volume concentration of germanium and wherein a bottom of the second structure is located below a bottommost surface of the first structures, wherein the first structure interfaces a first channel of the first multilayer channel and also interfaces a second channel of the first multilayer channel.