Abstract: Integrated circuit transistor structures and processes are disclosed that reduce n-type dopant diffusion, such as phosphorous or arsenic, from the source region and the drain region of a germanium n-MOS device into adjacent channel regions during fabrication. The n-MOS transistor device may include at least 70% germanium (Ge) by atomic percentage. In an example embodiment, source and drain regions of the transistor are formed using a low temperature, non-selective deposition process of n-type doped material. In some embodiments, the low temperature deposition process is performed in the range of 450 to 600 degrees C. The resulting structure includes a layer of doped mono-crystyalline silicon (Si), or silicon germanium (SiGe), on the source/drain regions. The structure also includes a layer of doped amorphous Si:P (or SiGe:P) on the surfaces of a shallow trench isolation (STI) region and the surfaces of contact trench sidewalls.

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 germanium (Ge)-rich channel transistors including one or more dopant diffusion barrier elements. The introduction of one or more dopant diffusion elements into at least a portion of a given source/drain (S/D) region helps inhibit the undesired diffusion of dopant (e.g., B, P, or As) into the adjacent Ge-rich channel region. In some embodiments, the elements that may be included in a given S/D region to help prevent the undesired dopant diffusion include at least one of tin and relatively high silicon. Further, in some such embodiments, carbon may also be included to help prevent the undesired dopant diffusion. In some embodiments, the one or more dopant diffusion barrier elements may be included in an interfacial layer between a given S/D region and the Ge-rich channel region and/or throughout at least a majority of a given S/D region. Numerous embodiments, configurations, and variations will be apparent.

Abstract: Techniques are disclosed for forming transistors employing non-selective deposition of source and drain (S/D) material. Non-selectively depositing S/D material provides a multitude of benefits over only selectively depositing the S/D material, such as being able to attain relatively higher dopant activation, steeper dopant profiles, and better channel strain, for example.

Abstract: Integrated circuit transistor structures are disclosed that reduce n-type dopant diffusion, such as phosphorous or arsenic, from the source region and the drain region of a germanium n-MOS device into adjacent insulator regions during fabrication. The n-MOS transistor device may include at least 75% germanium by atomic percentage. In an example embodiment, a dopant-rich insulator cap is deposited adjacent to the source and/or drain regions, to provide dopant diffusion reduction. In some embodiments, the dopant-rich insulator cap is doped with an n-type impurity including Phosphorous in a concentration between 1 and 10% by atomic percentage. In some embodiments, the dopant-rich insulator cap may have a thickness in the range of 10 to 100 nanometers and a height in the range of 10 to 200 nanometers.

Abstract: Integrated circuit transistor structures are disclosed that include a gate structure that is lattice matched to the underlying channel. In particular, the gate dielectric is lattice matched to the underlying semiconductor channel material, and in some embodiments, so is the gate electrode. In an example embodiment, single crystal semiconductor channel material and single crystal gate dielectric material that are sufficiently lattice matched to each other are epitaxially deposited. In some cases, the gate electrode material may also be a single crystal material that is lattice matched to the semiconductor channel material, thereby allowing the gate electrode to impart strain on the channel via the also lattice matched gate dielectric. A gate dielectric material that is lattice matched to the channel material can be used to reduce interface trap density (Dit). The techniques can be used in both planar and non-planar (e.g., finFET and nanowire) metal oxide semiconductor (MOS) transistor architectures.

Abstract: Integrated circuits include fins including an upper/channel region and a lower/sub-channel region, the lower region having a first chemical composition and opposing sidewalls adjacent to an insulator material, and the upper region having a second chemical composition. A first width indicates the distance between the opposing sidewalls of the lower region at a first location is at least 1 nm wider than a second width indicating the distance between the opposing sidewalls of the upper region at a second location, the first location being within 10 nm of the second location (or otherwise relatively close to one another). The first chemical composition is distinct from the second chemical composition and includes a surface chemical composition at an outer surface of the opposing sidewalls of the lower region and a bulk chemical composition therebetween, the surface chemical composition including one or more of oxygen, nitrogen, carbon, chlorine, fluorine, and sulfur.

Abstract: An integrated circuit (IC) includes a substrate that includes silicon. A first layer is on the substrate and includes a first monocrystalline semiconductor material, the first layer having a plurality of defects. A second layer is on the first layer and includes a second monocrystalline semiconductor material that includes germanium. A strained channel structure is above the first layer. A gate structure is at least above the channel structure. A source region is adjacent the channel structure. A drain region is adjacent the channel structure, such that the channel structure is laterally between the source region and the drain region.

Abstract: A replacement fin layer is deposited on a sub-fin layer in trenches isolated by an insulating layer on a substrate. The replacement fin layer has first component rich side portions and a second component rich core portion. The second component rich core portion is etched to generate a double fin structure comprising the first component rich fins.

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.

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: Methods of forming germanium channel structure are described. An embodiment includes forming a germanium fin on a substrate, wherein a portion of the germanium fin comprises a germanium channel region, forming a gate material on the germanium channel region, and forming a graded source/drain structure adjacent the germanium channel region. The graded source/drain structure comprises a germanium concentration that is higher adjacent the germanium channel region than at a source/drain contact region.

Abstract: Techniques are disclosed for performing silicon (Si) substrate modification to enable formation of a thin, relaxed germanium (Ge)-based layer on the modified Si substrate. The thin, relaxed, Ge-based layer (e.g., having a thickness of at most 500 nm) can then serve as a template for the growth of compressively strained PMOS channel material and tensile strained NMOS channel material to achieve gains in hole and electron mobility, respectively, in the channel regions of the devices. Such a relatively thin Ge-based layer can be formed with suitable surface quality/relaxation levels due to the modification of the Si substrate, where such modification may include depositing a modification layer or performing ion implantation in/on the Si substrate. The modification layer can be characterized by the nucleation of defects which predominantly terminate within the Si substrate or the Ge-based layer, rather than running through to the top of the Ge-based layer.

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: A trench is formed in an insulating layer to expose a native fin on a substrate. A replacement fin is deposited on the native fin in the trench. The replacement fin is trimmed laterally.

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: Integrated circuit transistor structures are disclosed that reduce n-type dopant diffusion, such as phosphorous or arsenic, from the source region and the drain region of a germanium n-MOS device into adjacent shallow trench isolation (STI) regions during fabrication. The n-MOS transistor device may include at least 75% germanium by atomic percentage. In an example embodiment, the structure includes an intervening diffusion barrier deposited between the n-MOS transistor and the STI region to provide dopant diffusion reduction. In some embodiments, the diffusion barrier may include silicon dioxide with carbon concentrations between 5 and 50% by atomic percentage. In some embodiments, the diffusion barrier may be deposited using chemical vapor deposition (CVD), atomic layer deposition (ALD), or physical vapor deposition (PVD) techniques to achieve a diffusion barrier thickness in the range of 1 to 5 nanometers.

Abstract: Integrated circuit transistor structures are disclosed that reduce n-type dopant diffusion, such as phosphorous or arsenic, from the source region and the drain region of a germanium n-MOS device into adjacent insulator regions during fabrication. The n-MOS transistor device may include at least 75% germanium by atomic percentage. In an example embodiment, a dopant-rich insulator cap is deposited adjacent to the source and/or drain regions, to provide dopant diffusion reduction. In some embodiments, the dopant-rich insulator cap is doped with an n-type impurity including Phosphorous in a concentration between 1 and 10% by atomic percentage. In some embodiments, the dopant-rich insulator cap may have a thickness in the range of 10 to 100 nanometers and a height in the range of 10 to 200 nanometers.

Abstract: Integrated circuits include fins including an upper/channel region and a lower/sub-channel region, the lower region having a first chemical composition and opposing sidewalls adjacent to an insulator material, and the upper region having a second chemical composition. A first width indicates the distance between the opposing sidewalls of the lower region at a first location is at least 1 nm wider than a second width indicating the distance between the opposing sidewalls of the upper region at a second location, the first location being within 10 nm of the second location (or otherwise relatively close to one another). The first chemical composition is distinct from the second chemical composition and includes a surface chemical composition at an outer surface of the opposing sidewalls of the lower region and a bulk chemical composition therebetween, the surface chemical composition including one or more of oxygen, nitrogen, carbon, chlorine, fluorine, and sulfur.

Abstract: Techniques are disclosed for forming diverse transistor channel materials enabled by a thin, inverse-graded, germanium (Ge)-based layer. The thin, inverse-graded, Ge-based layer (e.g., having a thickness of at most 500 nm) can then serve as a template for the growth of compressively strained PMOS channel material and tensile strained NMOS channel material to achieve gains in hole and electron mobility, respectively, in the channel regions of the devices. Such a relatively thin Ge-based layer can be formed with suitable surface quality/relaxation levels due to the inverse grading of the Ge concentration in the layer, where the Ge concentration is relatively greatest near the substrate and relatively lowest near the overlying channel material layer. In addition to the inverse-graded Ge concentration, the Ge-based layer may be characterized by the nucleation, and predominant containment, of defects at/near the interface between the substrate and the Ge-based layer.