Semiconductor structure and method for forming the same

A semiconductor structure, comprising:

• a gate stack wrapping around a plurality of nanostructures;
• a gate spacer layer alongside the gate stack;
• a semiconductor inner spacer layer alongside plurality of nanostructures below the gate spacer layer;
• and
• a source/drain feature alongside the semiconductor inner spacer layer, wherein a source/drain junction vertically extends in the semiconductor inner spacer and between extension lines of sidewalls of the gate spacer layer.

A method for forming a semiconductor structure, comprising:

• forming a fin structure in which first semiconductor layers and second semiconductor layers are stacked alternatingly;
• etching the fin structure to form a recess;
• recessing the first semiconductor layers to form notches between the second semiconductor layers;
• forming an inner spacer layer to cover sidewalls of the second semiconductor layers and fill the notches;
• forming a source/drain feature in the source/drain recess;
• and
• driving a dopant from the source/drain feature into the inner spacer layer to form a source/drain junction, wherein the source/drain junction vertically extends through a portion of the inner spacer layer covering the sidewalls of the second semiconductor layers.