A field effect transistor includes a source region and a drain region formed within and/or above openings in a dielectric capping mask layer overlying a semiconductor substrate and a gate electrode. A source-side silicide portion and a drain-side silicide portion are self-aligned to the source region and to the drain region, respectively.

A semiconductor device includes: a metal-oxide semiconductor (MOS) transistor on a substrate; a deep trench isolation structure in the substrate and around the MOS transistor; and a trap rich isolation structure in the substrate and surrounding the deep trench isolation structure. Preferably, the deep trench isolation structure includes a liner in the substrate and an insulating layer on the liner, in which the top surfaces of the liner and the insulating layer are coplanar. The trap rich isolation structure is made of undoped polysilicon and the trap rich isolation structure includes a ring surrounding the deep trench isolation structure according to a top view.

A semiconductor device includes a first gate structure disposed on a substrate and extending in a first direction. The first gate structure includes a first gate electrode, a first cap insulating layer disposed over the first gate electrode, first sidewall spacers disposed on opposing side faces of the first gate electrode and the first cap insulating layer and second sidewall spacers disposed over the first sidewall spacers. The semiconductor device further includes a first protective layer formed over the first cap insulating layer, the first sidewall spacers and the second sidewall spacers. The first protective layer has a π-shape having a head portion and two leg portions in a cross section along a second direction perpendicular to the first direction.

The present application discloses a semiconductor device with a contact having tapered profile and a method for fabricating the semiconductor device. The semiconductor device includes a substrate having a first region and a second region; a first gate structure positioned on the first region; and a second gate structure positioned on the second region; a first contact including a first lower portion positioned on a top surface of the first gate structure, and a first upper portion positioned on the first lower portion; and a second contact including a second lower portion positioned on a top surface of the second gate structure and a sidewall of the second gate structure, and a second upper portion positioned on the second lower portion. Sidewalls of the first lower portion are tapered and sidewalls of the second lower portion are substantially vertical.

A semiconductor device includes a semiconductor substrate, a first gate oxide layer, and a first source/drain doped region. The first gate oxide layer is disposed on the semiconductor substrate, and the first gate oxide layer includes a main portion and an edge portion having a sloping sidewall. The first source/drain doped region is disposed in the semiconductor substrate and located adjacent to the edge portion of the first gate oxide layer. The first source/drain doped region includes a first portion and a second portion. The first portion is disposed under the edge portion of the first gate oxide layer in a vertical direction, and the second portion is connected with the first portion.

A semiconductor device includes a semiconductor substrate, a pair of source/drain regions on the semiconductor substrate, and a gate structure on the semiconductor substrate and between the pair of source/drain regions. The gate structure includes a first metal layer and a second metal layer in contact with the first metal layer. A sidewall of the first metal layer and a top surface of the semiconductor substrate form a first included angle, a sidewall of the second metal layer and the top surface of the semiconductor substrate form a second included angle. The second included angle is different from the first included angle.

A semiconductor device includes a semiconductor substrate, a capacitor structure, a first contact plug, and a spacer. The capacitor structure is over the semiconductor substrate. The capacitor structure includes a bottom electrode, a capacitor dielectric, and a top electrode. The bottom electrode is over the semiconductor substrate. The capacitor dielectric is over a first portion of the bottom electrode. The top electrode is over the capacitor dielectric. The first contact plug is over and electrically connected to a second portion of the bottom electrode. The spacer is adjacent at least a sidewall of the second portion of the bottom electrode.

A semiconductor device includes a gate structure disposed on a substrate. The gate structure has a first sidewall and a second sidewall facing the first sidewall. A first impurity region is disposed within an upper portion of the substrate. The first impurity region is spaced apart from the first sidewall. A third impurity region is within the upper portion of the substrate. The third impurity region is spaced apart from the second sidewall. A first trench is disposed within the substrate between the first sidewall and the first impurity region. The first trench is spaced apart from the first sidewall. A first barrier insulation pattern is disposed within the first trench.

A field effect transistor includes a source region and a drain region formed within and/or above openings in a dielectric capping mask layer overlying a semiconductor substrate and a gate electrode. A source-side silicide portion and a drain-side silicide portion are self-aligned to the source region and to the drain region, respectively.

A method for fabricating semiconductor device includes the steps of first forming a gate structure on a substrate, forming a source/drain region adjacent to two sides of the gate structure, forming an epitaxial layer on the source/drain region, forming an interlayer dielectric (ILD) layer on the gate structure, forming a contact hole in the ILD layer to expose the epitaxial layer, forming a low stress metal layer in the contact hole, forming a barrier layer on the low stress metal layer, and forming an anneal process to form a first silicide layer and a second silicide layer.