Abstract: A semiconductor structure includes a substrate that includes a base, a plurality of channel layers on the base, and an isolation layer between each of the channel layers. The semiconductor structure also includes a gate on the substrate, spanning a top and a portion of sidewalls of the channel layers. The semiconductor structure also includes a sidewall structure on sidewalls at two sides of the gate, a source/drain region in the substrate at two sides of the gate and the sidewall structure, a source/drain electrical connection layer on the source/drain region, and an isolation structure between the source/drain electrical connection layer and the gate. The isolation structure includes a cavity, including a first cavity region and a second cavity region located on the first cavity region. A width of the second cavity region is smaller than a width of the first cavity region.

Abstract: Semiconductor structures and fabrication methods thereof are provided. The method includes providing a substrate; forming a stacked material structure on the substrate; and forming trenches in the stacked material structure. Bottoms of the trenches are in the first material layer, the trenches are arranged along a first direction and form an initial stacked structure sequentially including an initial first layer, an initial second layer and an initial third layer. The method also includes etching the initial third layer to form transitional third layers arranged along a second direction perpendicular to the first direction; removing a portion of the initial first layer and a portion of the initial second layer of the initial stacked structure at two sides along the second direction to form a stacked structure including a first layer, a second layer and the transitional third layers; and forming a gate structure.

Abstract: Semiconductor structures and fabrication methods thereof are provided. The method includes providing a substrate; forming a stacked material structure on the substrate; and forming trenches in the stacked material structure. Bottoms of the trenches are in the first material layer, the trenches are arranged along a first direction and form an initial stacked structure sequentially including an initial first layer, an initial second layer and an initial third layer. The method also includes etching the initial third layer to form transitional third layers arranged along a second direction perpendicular to the first direction; removing a portion of the initial first layer and a portion of the initial second layer of the initial stacked structure at two sides along the second direction to form a stacked structure including a first layer, a second layer and the transitional third layers; and forming a gate structure.