In a method of manufacturing a semiconductor device, a fin structure in which first semiconductor layers and second semiconductor layers are alternately stacked is formed over a substrate, a sacrificial gate structure is formed over the fin structure, a source/drain region of the fin structure is etched thereby forming a source/drain space, ends of the first semiconductor layers is laterally etched, an insulating layer is formed on a sidewall of the source/drain space, the insulating layer is partially etched, thereby forming one or more inner spacers on an etched end face of each of one or more first semiconductor layers and leaving a part of the insulating layer as a remaining insulating layer, and a source/drain epitaxial layer is formed in the source/drain space. After the source/drain epitaxial layer is formed, an end face of at least one of the second semiconductor layers is covered by the remaining insulating layer.

Semiconductor structures and methods of forming the same are provided. In an embodiment, an exemplary semiconductor structure includes a vertical stack of channel members disposed over a substrate, a gate structure wrapping around each channel member of the vertical stack of channel members, a dielectric feature disposed directly on the substrate and in direct contact with a portion of the vertical stack of channel members, and a source/drain feature disposed directly on the dielectric feature and electrically coupled to a remaining portion of the vertical stack of channel members.

Semiconductor structures and methods are provided. A semiconductor structure according to the present disclosure includes a substrate, a first semiconductor layer over the substrate, a second semiconductor layer over the first semiconductor layer and including a channel region sandwiched between a first source/drain region and a second source/drain region, a first plurality of nanostructures disposed over the channel region, a first leakage block layer over the first source/drain region, a second leakage block layer over the second source/drain region, a dielectric layer on the first leakage block layer, a first source/drain feature on the dielectric layer and in contact with first sidewalls of the first plurality of nanostructures, and a second source/drain feature disposed on the second leakage block layer and in contact with second sidewalls of the first plurality of nanostructures. The first leakage block layer and the second leakage block layer includes an undoped semiconductor material.

Semiconductor devices and methods are provided. A semiconductor device according to the present disclosure includes a first gate-all-around (GAA) transistor that includes a first plurality of channel members, and a second GAA transistor that includes a second plurality of channel members. The first plurality of channel members has a first pitch (P1) and the second plurality of channel members has a second pitch (P2) smaller than the first pitch (P1).

A method includes forming a pad layer. The pad layer includes a first portion over a first part of a semiconductor substrate, and a second portion over a second part of the semiconductor substrate. The first portion has a first thickness, and the second portion has a second thickness smaller than the first thickness. The semiconductor substrate is then annealed to form a first oxide layer over the first part of the semiconductor substrate, and a second oxide layer over the second part of the semiconductor substrate. The pad layer, the first oxide layer, and the second oxide layer are removed. A semiconductor layer is epitaxially grown over and contacting the first part and the second part of the semiconductor substrate.

Semiconductor devices and methods of manufacture are presented. In embodiments a method of manufacturing the semiconductor device includes forming a fin from a plurality of semiconductor materials, depositing a dummy gate over the fin, depositing a plurality of spacers adjacent to the dummy gate, removing the dummy gate to form an opening adjacent to the plurality of spacers, widening the opening adjacent to a top surface of the plurality of spacers, after the widening, removing one of the plurality of semiconductor materials to form nanowires, and depositing a gate electrode around the nanowires.

The present disclosure provides a semiconductor device and a method of forming the same. The semiconductor device includes a fin-shape base protruding from a semiconductor substrate. A top surface of the semiconductor substrate is in a (100) crystal plane, and a top surface of the fin-shape base is in a (110) crystal plane. The semiconductor device also includes channel members disposed over the top surface of the fin-shape base, a gate structure wrapping around at least one of channel members, a gate spacer extending along a sidewall of the gate structure, a source/drain feature abutting the channel members, and a dopant-free epitaxial feature under the source/drain feature. A top surface of the source/drain feature is in a (110) crystal plane. A top surface of the dopant-free epitaxial feature is in a (110) crystal plane.

Semiconductor structures and methods of forming the same are provided. In an embodiment, an exemplary semiconductor structure includes a first transistor. The first transistor includes a first gate structure wrapping around a plurality of first nanostructures disposed over a substrate, a first source/drain feature electrically coupled to a topmost nanostructure of the plurality of first nanostructures and isolated from a bottommost nanostructure of the plurality of first nanostructures by a first dielectric layer, and a first semiconductor layer disposed between the substrate and the first source/drain feature, wherein the first source/drain feature is in direct contact with a top surface of the first semiconductor layer.

Provided is a semiconductor device which includes: a substrate; a channel structure on the substrate; a source/drain pattern connected to the channel structure; a gate structure on the channel structure; an inner spacer structure comprising an inner spacer between the source/drain pattern and the gate structure, and an inner spacer residue connected to the inner spacer structure; and an inner isolation structure between the inner spacer residue and a bottom surface of the source/drain pattern.

Provided is a semiconductor device which includes: a 1.sup.st source/drain pattern for a 1.sup.st transistor; a 2.sup.nd source/drain pattern for a 2.sup.nd transistor, above the 1.sup.st source/drain pattern, the 2.sup.nd source/drain pattern having a smaller width than the 1.sup.st source/drain pattern in a channel-width direction; a 1.sup.st isolation layer surrounding the 1.sup.st source/drain pattern; a 2.sup.nd isolation layer surrounding the 2.sup.nd source/drain pattern, the 1.sup.st and 2.sup.nd isolation layers including a first material; a liner surrounding the 1.sup.st source/drain pattern, the liner including a 2.sup.nd material; and a contact structure on the 1.sup.st source/drain pattern, wherein the contact structure penetrates the 2.sup.nd isolation layer and the liner to contact the 1.sup.st source/drain pattern without penetrating the 1.sup.st isolation layer.