A method includes forming a gate stack over a semiconductor region, and forming a first gate spacer on a sidewall of the gate stack. The first gate spacer includes an inner sidewall spacer, and a dummy spacer portion on an outer side of the inner sidewall spacer. The method further includes removing the dummy spacer portion to form a trench, and forming a dielectric layer to seal a portion of the trench as an air gap. The air gap and the inner sidewall spacer in combination form a second gate spacer. A source/drain region is formed to have a portion on an outer side of the second gate spacer.

A semiconductor structure includes a first device and a second device. The first device includes: a first gate structure formed over an active region and a first air spacer disposed adjacent to the first gate structure. The second device includes: a second gate structure formed over an isolation structure and a second air spacer disposed adjacent to the second gate structure. The first air spacer and the second air spacer have different sizes.

The present application discloses a method for fabricating semiconductor device with a graphene-based element. The method includes providing a substrate; forming a stacked gate structure over the substrate; forming first spacers on sidewalls of the gate stack structure, wherein the first spacers comprise graphene; forming sacrificial spacers on sidewall of the first spacers; and forming second spacers on sidewall of the sacrificial spacers.

A method for fabricating a metal gate structure includes following steps. A substrate is provided and followed by forming a high-K dielectric layer on the substrate. Then, an oxygen-containing titanium nitride layer is formed on the high-K dielectric layer. Next, an amorphous silicon layer is formed on the oxygen-containing titanium nitride layer and followed by performing an annealing process to drive oxygen in the oxygen-containing titanium nitride layer to the high-K dielectric layer.

A semiconductor device includes a semiconductor substrate and a semiconductor fin on the semiconductor substrate and a fin isolation structure on the semiconductor substrate. The fin isolation structure has an air gap dividing the semiconductor fin into two portions of the semiconductor fin, in which the air gap extends into the semiconductor substrate for a distance. The fin isolation structure includes a dielectric cap layer capping a top of the air gap, in which the dielectric cap layer is spaced apart from a bottom of the air gap.

A method of scaling a nonvolatile trapped-charge memory device and the device made thereby is provided. In an embodiment, the method includes forming a channel region including polysilicon electrically connecting a source region and a drain region in a substrate. A tunneling layer is formed on the substrate over the channel region by oxidizing the substrate to form an oxide film and nitridizing the oxide film. A multi-layer charge trapping layer including an oxygen-rich first layer and an oxygen-lean second layer is formed on the tunneling layer, and a blocking layer deposited on the multi-layer charge trapping layer. In one embodiment, the method further includes a dilute wet oxidation to densify a deposited blocking oxide and to oxidize a portion of the oxygen-lean second layer.

A semiconductor device includes a fin-type active area, nanosheets, a gate, a source/drain region, and insulating spacers. The fin-type active area protrudes from a substrate in a first direction. The nanosheets are spaced from an upper surface of the fin-type active area and include channel regions. The gate is over the fin-type active area. The source/drain region is connected to the nanosheets. The insulating spacers are in the fin-type active area and between the nanosheets. Air spaces are between the insulating spacers and the source/drain region based on positions of the insulating spacers.

A method for producing a field-effect semiconductor device includes providing a semiconductor body with a first surface defining a vertical direction, defining an active area, forming a vertical trench from the first surface into the semiconductor body, forming a field dielectric layer at least on a side wall and a bottom wall of the vertical trench, depositing a conductive layer on the field dielectric layer, forming a closed cavity on the conductive layer in the vertical trench, and forming an insulated gate electrode on the closed cavity in the vertical trench.

A method includes removing a dummy gate stack to form a first trench between gate spacers, forming a replacement gate stack in the first trench, recessing the replacement gate stack to form a second trench between the gate spacers, selectively depositing a conductive capping layer in the second trench, forming a dielectric hard mask in the second trench and over the conductive capping layer, and etching the dielectric hard mask using an etching gas to form an opening in the dielectric hard mask. The replacement gate stack is revealed to the opening. The conductive capping layer is more resistant to the etching gas than the replacement gate stack. The method further comprises forming a gate contact plug over and contacting the conductive capping layer.

A semiconductor device that includes a gate structure on a channel region of a semiconductor device. Source and drain regions may be present on opposing sides of the channel region. The semiconductor device may further include a composite gate sidewall spacer present on a sidewall of the gate structure. The composite gate sidewall spacer may include a first composition portion having an air gap encapsulated therein, and a second composition portion that is entirely solid and present atop the first composition portion.