Semiconductor structure with nitrided inner spacers and method for manufacturing the same

A method for manufacturing a semiconductor structure, comprising:

• forming a stack portion including a channel feature and a sacrificial feature disposed beneath the channel feature;
• forming a dummy gate portion on the stack portion;
• forming a gate spacer on the stack portion and at a side of the dummy gate portion;
• patterning the stack portion to form a source/drain recess in the stack portion;
• replacing an end portion of the sacrificial feature with an inner spacer through the source/drain recess;
• treating the inner spacer and the gate spacer with a nitrogen-containing plasma to form a lateral nitrided portion in the inner spacer and a nitrogen-introduced outer portion in the gate spacer;
• and
• performing a removing process on the inner spacer and the gate spacer, such that the nitrogen-introduced outer portion of the gate spacer is removed, while the lateral nitrided portion of the inner spacer is partially retained.

A method for manufacturing a semiconductor structure, comprising:

• forming a stack portion on a base portion, the stack portion including a channel feature and a sacrificial feature which is disposed beneath the channel feature;
• forming a dummy gate portion on the stack portion;
• forming a gate spacer on the stack portion and at a side of the dummy gate portion;
• patterning the stack portion to form a source/drain recess, thereby exposing the base portion;
• replacing an end portion of the sacrificial feature with an inner spacer through the source/drain recess;
• forming a dielectric isolation layer on the base portion, the dielectric isolation layer being located at a bottom of the source/drain recess;
• performing a treating process on the inner spacer, the gate spacer and the dielectric isolation layer using a nitrogen-containing plasma to form a lateral nitrided portion in the inner spacer, a nitrogen-introduced outer portion in the gate spacer, and an upper nitrided portion in the dielectric isolation layer;
• and
• performing a removing process on the inner spacer, the gate spacer and the dielectric isolation layer, such that the nitrogen-introduced outer portion of the gate spacer is removed, while the lateral nitrided portion of the inner spacer and the upper nitrided portion of the dielectric isolation layer are partially retained.