A method for fabricating a semiconductor device includes: forming a gate structure including a source side and a drain side over a substrate, wherein a dielectric material and a columnar crystal grain material are stacked over the substrate; doping a chemical species on the drain side of the gate structure; and exposing the gate structure doped with the chemical species to a re-growth process in order to thicken the dielectric material on the drain side of the gate structure.

The present disclosure describes an exemplary replacement gate process that forms spacer layers in a gate stack to mitigate time dependent dielectric breakdown (TDDB) failures. For example, the method can include a partially fabricated gate structure with a first recess. A spacer layer is deposited into the first recess and etched with an anisotropic etchback (EB) process to form a second recess that has a smaller aperture than the first recess. A metal fill layer is deposited into the second recess.

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.

An integrated chip comprises a substrate, an isolation structure and a gate structure. The isolation structure is disposed in the substrate and enclosing an active region in the substrate. The active region comprises a source region and a drain region separated by a channel region along a first direction. The gate structure is disposed over the channel region and comprising a first gate electrode region and a second gate electrode region arranged one next to another laterally along a second direction perpendicular to the first direction. The first gate electrode region has a first composition, and the second gate electrode region has a second composition different than the first composition.

A work function metal gate device includes a gate, a drift region, a source, a drain and a first isolation structure. The gate includes a convex stair-shaped work function metal stack or a concave stair-shaped work function metal stack disposed on a substrate. The drift region is disposed in the substrate below a part of the gate. The source is located in the substrate and the drain is located in the drift region beside the gate. The first isolation structure is disposed in the drift region between the gate and the drain.

A structure of field-effect transistor includes a silicon layer of a silicon-on-insulator structure. A gate structure layer in a line shape is disposed on the silicon layer, wherein the gate structure layer includes a first region and a second region abutting to the first region. Trench isolation structures in the silicon layer are disposed at two sides of the gate structure layer, corresponding to the second region. The second region of the gate structure layer is disposed on the silicon layer and overlaps with the trench isolation structure. A source region and a drain region are disposed in the silicon layer at the two sides of the gate structure layer, corresponding to the first region. The second region of the gate structure layer includes a conductive-type junction portion.

An integrated chip includes a substrate, an isolation structure and a poly gate structure. The isolation structure includes dielectric materials within the substrate and having sidewalls defining an active region. The active region has a channel region, a source region, and a drain region separated from the source region by the channel region along a first direction. The source region has a first width along a second direction perpendicular to the first direction, the drain region has a second width along the second direction, and the channel region has a third width along the second direction and larger than the first and second widths. The poly gate structure extends over the channel region. The poly gate structure includes a first doped region having a first type of dopants and a second doped region having a second type of dopants. The second type is different from the first type.

Disclosed is a semiconductor device for improving a gate induced drain leakage and a method for fabricating the same, and the method for fabricating semiconductor device may include forming a trench in a substrate; forming a gate dielectric layer over the trench, embedding a first dipole inducing portion in the gate dielectric layer on a lower side of the trench, filling a lower gate over the first dipole inducing portion, embedding a second dipole inducing portion in the gate dielectric layer on an upper side of the trench and forming an upper gate over the lower gate.

A structure of field-effect transistor includes a silicon layer of a silicon-on-insulator structure. A gate structure layer in a line shape is disposed on the silicon layer, wherein the gate structure layer includes a first region and a second region abutting to the first region. Trench isolation structures in the silicon layer are disposed at two sides of the gate structure layer, corresponding to the second region. The second region of the gate structure layer is disposed on the silicon layer and overlaps with the trench isolation structure. A source region and a drain region are disposed in the silicon layer at the two sides of the gate structure layer, corresponding to the first region. The second region of the gate structure layer includes a conductive-type junction portion.

A work function metal gate device includes a gate, a drift region, a source, a drain and a first isolation structure. The gate includes a convex stair-shaped work function metal stack or a concave stair-shaped work function metal stack disposed on a substrate. The drift region is disposed in the substrate below a part of the gate. The source is located in the substrate and the drain is located in the drift region beside the gate. The first isolation structure is disposed in the drift region between the gate and the drain.