Abstract: Techniques are disclosed for forming transistors employing a source/drain (S/D) cap layer for Ge-rich S/D regions to, e.g., help suppress contact metal piping. Contact metal piping occurs when metal material from the S/D contact region diffuses into the channel region, which can lead to a reduction of the effective gate length and can even cause device shorting/failure. The S/D cap layer includes silicon (Si) and/or carbon (C) to help suppress the continuous reaction of contact metal material with the Ge-rich S/D material (e.g., Ge or SiGe with at least 50% Ge concentration by atomic percentage), thereby reducing or preventing the diffusion of metal from the S/D contact region into the channel region as subsequent processing occurs. In addition, the Si and/or C-based S/D cap layer is more selective to contact trench etch than the doped Ge-rich material included in the S/D region, thereby increasing controllability during contact trench etch processing.

Abstract: Techniques are disclosed for forming germanium (Ge)-rich channel transistors including a carbon-based dopant diffusion barrier. As can be understood based on this disclosure, the introduction of carbon into at least a portion of a given source/drain (S/D) region helps inhibit the diffusion of dopant (e.g., B, P, or As) into the adjacent Ge-rich channel region. The carbon may be: included in an interfacial layer located between a given S/D region and its corresponding Ge-rich channel region, where that interfacial layer acts as a dopant diffusion barrier layer to help prevent dopant included in the bulk S/D material from diffusing into the Ge-rich channel region; included as an alloying element in the bulk S/D material, such that carbon is included throughout at least a majority of a given S/D region; or utilized in a combination of the two aforementioned approaches. Numerous embodiments, configurations, and variations will be apparent.

Abstract: An apparatus is provided which comprises: a semiconductor region on a substrate, a gate stack on the semiconductor region, a source region of doped semiconductor material on the substrate adjacent a first side of the semiconductor region, a drain region of doped semiconductor material on the substrate adjacent a second side of the semiconductor region, and a transition region in the drain region, adjacent the semiconductor region, wherein the transition region comprises varying dopant concentrations that increase in a direction away from the semiconductor region. Other embodiments are also disclosed and claimed.

Abstract: Techniques are disclosed for forming transistors employing a carbon-based etch stop layer (ESL) for preserving source and drain (S/D) material during contact trench etch processing. As can be understood based on this disclosure, carbon-based layers can provide increased resistance for etch processing, such that employing a carbon-based ESL on S/D material can preserve that S/D material during contact trench etch processing. This is due to carbon-based layers being able to provide more robust (e.g., more selective) etch selectivity during contact trench etch processing than the S/D material it is preserving (e.g., Si, SiGe, Ge, group III-V semiconductor material) and other etch stop layers (e.g., insulator material-based etch stop layers). Employing a carbon-based ESL enables a given S/D region to protrude from shallow trench isolation (STI) material prior to contact metal deposition, thereby providing more surface area for making contact to the given S/D region, which improves transistor performance.

Abstract: 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.

Abstract: Methods of forming a strained channel device utilizing dislocations disposed in source/drain structures are described. Those methods and structures may include forming a thin silicon germanium material in a source/drain opening of a device comprising silicon, wherein multiple dislocations are formed in the silicon germanium material. A source/drain material may be formed on the thin silicon germanium material, wherein the dislocations induce a tensile strain in a channel region of the device.

Abstract: Transistor devices may be formed having a buffer between an active channel and a substrate, wherein the active channel and a portion of the buffer form a gated region. The active channel may comprise a low band-gap material on a sub-structure, e.g. the buffer, between the active channel and the substrate. The sub-structure may comprise a high band-gap material having a desired conduction band offset, such that leakage may be arrested without significant impact on electron mobility within the active channel. In an embodiment, the active channel and the sub-structure may be formed in a narrow trench, such that defects due to lattice mismatch between the active channel and the sub-structure are terminated in the sub-structure.

Abstract: Techniques are disclosed for forming transistors on the same substrate with varied channel materials. The techniques include forming a replacement material region in the substrate, such region used to form a plurality of fins therefrom, the fins used to form transistor channel regions. In an example case, the substrate may comprise Si and the replacement materials may include Ge, SiGe, and/or at least one III-V material. The replacement material regions can have a width sufficient to ensure a substantially planar interface between the replacement material and the substrate material. Therefore, the fins formed from the replacement material regions can also have a substantially planar interface between the replacement material and the substrate material. One example benefit from being able to form replacement material channel regions with such substantially planar interfaces can include at least a 30 percent improvement in current flow at a fixed voltage.

Abstract: Disclosed herein are transistor amorphous interlayer arrangements, and related methods and devices. For example, in some embodiments, transistor amorphous interlayer arrangement may include a channel material and a transistor source/drain stack. The transistor source/drain stack may include a transistor electrode material configured to be a transistor source/drain contact, i.e. either a source contact or a drain contact of the transistor, and a doped amorphous semiconductor material disposed between the transistor electrode material and the channel material.

Abstract: Techniques are disclosed for sculpting and cladding the channel region of fins on a semiconductor substrate during a replacement gate process (e.g., for transistor channel applications). The sculpting and cladding can be performed when the channel region of the fins are re-exposed after the dummy gate used in the replacement gate process is removed. The sculpting includes performing a trim etch on the re-exposed channel region of the fins to narrow a width of the fins (e.g., by 2-6 nm). A cladding layer, which may include germanium (Ge) or silicon germanium (SiGe), can then be deposited on the trimmed fins, leaving the source/drain regions of the fins unaffected. The sculpting and cladding may be performed in-situ or without air break to increase the quality of the trimmed fins (e.g., as compared to an ex-situ process).

Abstract: An embodiment includes an apparatus comprising: a fin structure on a substrate, the fin structure including fin top and bottom portions, a channel including a majority carrier, and an epitaxial (EPI) layer; an insulation layer including insulation layer top and bottom portions adjacent the fin top and bottom portions; wherein (a) the EPI layer comprises one or more of group IV and lll-V materials, (b) the fin bottom portion includes a fin bottom portion concentration of dopants of opposite polarity to the majority carrier, (c) the fin top portion includes a fin top portion concentration of the dopants less than the fin bottom portion concentration, (d) the insulation layer bottom portion includes an insulation layer bottom portion concentration of the dopants, and (e) the insulation layer top portion includes an insulation top layer portion concentration greater than the insulation bottom portion concentration. Other embodiments are described herein.

Abstract: Transistor fin elements (e.g., fin or tri gate) may be modified by radio frequency (RF) plasma and/or thermal processing for purpose of dimensional sculpting. The etched, thinned fins may be formed by first forming wider single crystal fins, and after depositing trench oxide material between the wider fins, etching the wider fins using a second etch to form narrower single crystal fins having undamaged top and sidewalls for epitaxially growing active channel material. The second etch may remove a thickness of between a 1 nm and 15 nm of the top surfaces and the sidewalls of the wider fins. It may remove the thickness using (1) chlorine or fluorine based chemistry using low ion energy plasma processing, or (2) low temperature thermal processing that does not damage fins via energetic ion bombardment, oxidation or by leaving behind etch residue that could disrupt the epitaxial growth quality of the second material.

Abstract: Methods of forming a strained channel device utilizing dislocations disposed in source/drain structures are described. Those methods and structures may include forming a thin silicon germanium material in a source/drain opening of a device comprising silicon, wherein multiple dislocations are formed in the silicon germanium material. A source/drain material may be formed on the thin silicon germanium material, wherein the dislocations induce a tensile strain in a channel region of the device.

Abstract: 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.

Abstract: Techniques are disclosed for customization of fin-based transistor devices to provide a diverse range of channel configurations and/or material systems, and within the same integrated circuit die. In accordance with an embodiment, sacrificial fins are cladded and then removed thereby leaving the cladding layer as a pair of standalone fins. Once the sacrificial fin areas are filled back in with a suitable insulator, the resulting structure is fin-on-insulator. The new fins can be configured with any materials by using such a cladding-on-core approach. The resulting fin-on-insulator structure is favorable, for instance, for good gate control while eliminating or otherwise reducing sub-channel source-to-drain (or drain-to-source) leakage current. In addition, parasitic capacitance from channel-to-substrate is significantly reduced.

Abstract: Techniques are disclosed for backside source/drain (S/D) replacement for semiconductor devices with metallization on both sides (MOBS). The techniques described herein provide methods to recover or otherwise facilitate low contact resistance, thereby reducing or eliminating parasitic external resistance that degrades transistor performance. In some cases, the techniques include forming sacrificial S/D material and a seed layer during frontside processing of a device layer including one or more transistor devices. The device layer can then be inverted and bonded to a host wafer. A backside reveal of the device layer can then be performed via grinding, etching, and/or CMP processes. The sacrificial S/D material can then be removed through backside S/D contact trenches using the seed layer as an etch stop, followed by the formation of relatively highly doped final S/D material grown from the seed layer, to provide enhanced ohmic contact properties. Other embodiments may be described and/or disclosed.

Abstract: Techniques are disclosed for forming nanowire transistors employing carbon-based layers. Carbon is added to the sacrificial layers and/or non-sacrificial layers of a multilayer stack forming one or more nanowires in the transistor channel region. Such carbon-based layers reduce or prevent diffusion and intermixing of the sacrificial and non-sacrificial portions of the multilayer stack. The reduction of diffusion/intermixing can allow for the originally formed layers to effectively maintain their original thicknesses, thereby enabling the formation of relatively more nanowires for a given channel region height because of the more accurate processing scheme. The techniques can be used to benefit group IV semiconductor material nanowire devices (e.g., devices including Si, Ge, and/or SiGe) and can also assist with the selective etch processing used to form the nanowires.

Abstract: Techniques are disclosed for fabricating nanowire transistors using directional selective etching. Generally, a selective wet etch employing a given etchant can be used to remove at least one “select material” while not removing other material exposed to the etch (or removing that other material at a relatively slower rate). The techniques described herein expand upon such selective etch processing by including a directional component. A directional selective etch may include a selective etch that only (or primarily) removes the select material in a targeted direction and/or that discriminates against removal of material in a non-targeted direction.

Abstract: Integrated circuit transistor structures are disclosed that include a single crystal buffer structure that is lattice matched to the underlying single crystal silicon substrate. The buffer structure may be used to reduce sub-fin leakage in non-planar transistors, but can also be used in planar configurations. In some embodiments, the buffer structure is a single continuous layer of high bandgap dielectric material that is lattice matched to silicon. The techniques below can be utilized on NMOS and PMOS transistors, including any number of group IV and III-V semiconductor channel materials.

Abstract: Techniques are disclosed for forming increasing channel region tensile strain in n-MOS devices. In some cases, increased channel region tensile strain can be achieved via S/D material engineering that deliberately introduces dislocations in one or both of the S/D regions to produce tensile strain in the adjacent channel region. In some such cases, the S/D material engineering to create desired dislocations may include using a lattice mismatched epitaxial S/D film adjacent to the channel region. Numerous material schemes for achieving multiple dislocations in one or both S/D regions will be apparent in light of this disclosure. In some cases, a cap layer can be formed on an S/D region to reduce contact resistance, such that the cap layer is an intervening layer between the S/D region and S/D contact. The cap layer includes different material than the underlying S/D region and/or a higher dopant concentration to reduce contact resistance.