A semiconductor device includes a gate structure on a substrate, a single diffusion break (SDB) structure adjacent to the gate structure, a first spacer adjacent to the gate structure, a second spacer adjacent to the SDB structure, a source/drain region between the first spacer and the second spacer, an interlayer dielectric (ILD) layer around the gate structure and the SDB structure, and a contact plug in the ILD layer and on the source/drain region. Preferably, a top surface of the second spacer is lower than a top surface of the first spacer.

A field effect transistor (FET) includes a substrate; a channel material located on the substrate, the channel material comprising one of graphene or a nanostructure; a gate located on a first portion of the channel material; and a contact aligned to the gate, the contact comprising one of a metal silicide, a metal carbide, and a metal, the contact being located over a source region and a drain region of the FET, the source region and the drain region comprising a second portion of the channel material.

Various embodiments of the present disclosure provide a method for forming a recessed gate electrode that has high thickness uniformity. A gate dielectric layer is deposited lining a recess, and a multilayer film is deposited lining the recess over the gate dielectric layer. The multilayer film comprises a gate electrode layer, a first sacrificial layer over the gate dielectric layer, and a second sacrificial layer over the first sacrificial dielectric layer. A planarization is performed into the second sacrificial layer and stops on the first sacrificial layer. A first etch is performed into the first and second sacrificial layers to remove the first sacrificial layer at sides of the recess. A second etch is performed into the gate electrode layer using the first sacrificial layer as a mask to form the recessed gate electrode. A third etch is performed to remove the first sacrificial layer after the second etch.

Techniques are disclosed for improved integration of germanium (Ge)-rich p-MOS source/drain contacts to, for example, reduce contact resistance. The techniques include depositing the p-type Ge-rich layer directly on a silicon (Si) surface in the contact trench location, because Si surfaces are favorable for deposition of high quality conductive Ge-rich materials. In one example method, the Ge-rich layer is deposited on a surface of the Si substrate in the source/drain contact trench locations, after removing a sacrificial silicon germanium (SiGe) layer previously deposited in the source/drain locations. In another example method, the Ge-rich layer is deposited on a Si cladding layer in the contact trench locations, where the Si cladding layer is deposited on a functional p-type SiGe layer. In some cases, the Ge-rich layer comprises at least 50% Ge (and may contain tin (Sn) and/or Si) and is boron (B) doped at levels above 1E20 cm.sup.3.

A semiconductor device structure is provided. The semiconductor device structure includes a semiconductor substrate. The semiconductor device structure includes a gate stack over the semiconductor substrate. The semiconductor device structure includes spacers over opposite sidewalls of the gate stack. The spacers and the gate stack surround a recess over the gate stack. The semiconductor device structure includes a first insulating layer over the gate stack and an inner wall of the recess. The semiconductor device structure includes a second insulating layer over the first insulating layer. Materials of the first insulating layer and the second insulating layer are different, and a first thickness of the first insulating layer is less than a second thickness of the second insulating layer.

Techniques are disclosed for forming transistor devices having reduced parasitic contact resistance relative to conventional devices. The techniques can be implemented, for example, using a standard contact stack such as a series of metals on, for example, silicon or silicon germanium (SiGe) source/drain regions. In accordance with one example such embodiment, an intermediate boron doped germanium layer is provided between the source/drain and contact metals to significantly reduce contact resistance. Numerous transistor configurations and suitable fabrication processes will be apparent in light of this disclosure, including both planar and non-planar transistor structures (e.g., FinFETs), as well as strained and unstrained channel structures. Graded buffering can be used to reduce misfit dislocation. The techniques are particularly well-suited for implementing p-type devices, but can be used for n-type devices if so desired.

An integrated circuit structure includes a gate stack over a semiconductor substrate, and an opening extending into the semiconductor substrate, wherein the opening is adjacent to the gate stack. A first silicon germanium region is disposed in the opening, wherein the first silicon germanium region has a first germanium percentage. A second silicon germanium region is over the first silicon germanium region. The second silicon germanium region comprises a portion in the opening. The second silicon germanium region has a second germanium percentage greater than the first germanium percentage. A silicon cap substantially free from germanium is over the second silicon germanium region.

An electrical device including a first semiconductor device having a silicon and germanium containing source and drain region, and a second semiconductor device having a silicon containing source and drain region. A first device contact to at least one of said silicon and germanium containing source and drain region of the first semiconductor device including a metal liner of an aluminum titanium and silicon alloy and a first tungsten fill. A second device contact is in contact with at least one of the silicon containing source and drain region of the second semiconductor device including a material stack of a titanium oxide layer and a titanium layer. The second device contact may further include a second tungsten fill.

A method of making a semiconductor device includes forming a source/drain region on a substrate; disposing a gate stack on the substrate and adjacent to the source/drain region, the gate stack including a gate spacer along a sidewall of the gate stack; disposing an inter-level dielectric (ILD) layer on the source/drain region and the gate stack; removing a portion of the ILD layer on the source/drain region to form a source/drain contact pattern; filling the source/drain contact pattern with a layer of silicon material, the layer of silicon material being in contact with the source/drain region and in contact with the gate spacer; depositing a metallic layer over the first layer of silicon material; and performing a silicidation process to form a source/drain contact including a silicide.

A semiconductor device includes a substrate, a gate electrode on the substrate, an insulating layer on the gate electrode, first and second lower vias in the insulating layer, first and second lower metal lines provided on the insulating layer and respectively connected to the first and second lower vias, and first and second upper metal lines provided on and respectively connected to the first and second lower metal lines. When viewed in a plan view, the first lower via is overlapped with the second upper metal line, and the second lower via is overlapped with the first upper metal line.