In an embodiment, a structure includes: a semiconductor substrate; a gate spacer over the semiconductor substrate, the gate spacer having an upper portion and a lower portion, a first width of the upper portion decreasing continually in a first direction extending away from a top surface of the semiconductor substrate, a second width of the lower portion being constant along the first direction; a gate stack extending along a first sidewall of the gate spacer and the top surface of the semiconductor substrate; and an epitaxial source/drain region adjacent a second sidewall of the gate spacer.

Semiconductor devices and methods for manufacturing the same are provided. In one embodiment, the method may include: forming a first shielding layer on a substrate, and forming one of source and drain regions with the first shielding layer as a mask; forming a second shielding layer on the substrate, and forming the other of the source and drain regions with the second shielding layer as a mask; removing a portion of the second shielding layer which is next to the other of the source and drain regions; forming a gate dielectric layer, and forming a gate conductor as a spacer on a sidewall of a remaining portion of the second shielding layer; and forming a stressed interlayer dielectric layer on the substrate.

The present disclosure provides a method for preparing a semiconductor memory device with air gaps between conductive features. The method includes forming an isolation layer defining a first active region in a substrate; forming a first doped region in the first active region; forming a first word line buried in a first trench adjacent to the first doped region; and forming a high-level bit line contact positioned on the first doped region; forming a first air gap surrounding the high-level bit line contact. The forming of the first word line comprises: forming a lower electrode structure and an upper electrode structure on the lower electrode structure. The forming of the upper electrode structure comprises: forming a source layer substantially covering a sidewall of the first trench; forming a conductive layer on the source layer; and forming a work-function adjustment layer disposed between the source layer and the conductive layer.

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 semiconductor device includes a first gate electrode structure having a first gate insulating layer on a substrate and a first gate electrode on the first gate insulating layer. A first spacer structure includes a first spacer and a second spacer on side walls of the first gate electrode structure. The first spacer is disposed between the second spacer and the first gate electrode. A source/drain region is disposed on opposite sides of the first gate electrode structure. The first gate electrode includes a lower part of the first gate electrode, an upper part of the first gate electrode disposed on the lower part of the first gate electrode, and the first spacer is disposed on the side wall of the upper pan of the first gate electrode and is not disposed on the side wall of the lower part of the first gate electrode.

A power MOSFET includes a substrate, a semiconductor layer, a first gate, a second gate, a thermal oxide layer, a first CVD oxide layer, and a gate oxide layer. The semiconductor layer is formed on the substrate and has at least one trench. The first gate is located inside the trench. The second gate is located inside the trench on the first gate, wherein the second gate has a first portion and a second portion, and the second portion is located between the semiconductor layer and the first portion. The thermal oxide layer is located between the first gate and the semiconductor layer. The first CVD oxide layer is located between the first gate and the second gate. The gate oxide layer is generally located between the second gate and the semiconductor layer.

Disclosed is a lateral double-diffused metal oxide semiconductor field effect transistor (LDMOSFET) with a replacement metal gate (RMG) structure that includes a first section, which traverses a semiconductor body at a channel region in a first-type well, and a second section, which is adjacent to the first section and which traverses the semiconductor body at a drain drift region in a second-type well. The RMG structure includes, in both sections, a first-type work function layer and a second-type work function layer on the first-type work function layer. However, the thickness of the first-type work function layer in the first section is greater than the thickness in the second section such that the RMG structure is asymmetric. Thus, threshold voltage (Vt) at the first section is greater than Vt at the second section and the LDMOSFET has a relatively high breakdown voltage (BV). Also disclosed are methods for forming the LDMOSFET.

A transistor and a method of forming the transistor are provided. The method includes forming a first interlayer dielectric layer on a substrate, forming an opening through the first interlayer dielectric layer, and forming a work function layer over side surfaces and a bottom of the opening. The method further includes forming a gate electrode layer over the work function layer, removing at least a portion of the work function layer over side surfaces of the gate electrode layer to form grooves, and forming a protection layer in the grooves.

A method of making a transistor for an integrated circuit includes providing a substrate and forming a dummy gate for the transistor within a gate trench on the substrate. The gate trench includes sidewalls, a trench bottom, and a trench centerline extending normally from a center portion of the trench bottom. The dummy gate is removed from the gate trench. A gate dielectric layer is disposed within the gate trench. A gate work-function metal layer is disposed over the gate dielectric layer, the work-function metal layer including a pair of corner regions proximate the trench bottom. An angled implantation process is utilized to implant a work-function tuning species into the corner regions at a tilt angle relative to the trench centerline, the tilt angle being greater than zero.

The present disclosure provides a semiconductor structure. The semiconductor structure comprises a semiconductor substrate comprising two source/drain regions, a gate stack over the semiconductor substrate and between the source/drain regions, and a spacer over the semiconductor substrate and surrounding the gate stack. The spacer comprises a carbon-containing layer and a carbon-free layer.