Showing papers by "Jack T. Kavalieros published in 2020"

High Speed Memory Operation in Channel-Last, Back-gated Ferroelectric Transistors

Abstract: Scaled ferroelectric transistors (L g =76 nm) in a back- gated configuration are fabricated with a channel-last process flow. Using this approach, optimization of the ferroelectric gate oxide film can be decoupled from that of the semiconductor channel to reduce parasitic interfaces. As a result, ferroelectric transistors with 3σ memory window for fast programming time of 10 ns (including an instantaneous read-after-write) at 1.8 V and high endurance of 1012 cycles are demonstrated for the first time.

Anti-ferroelectric Hf x Zr 1-x O 2 Capacitors for High-density 3-D Embedded-DRAM

Abstract: In this paper, a three-dimensional (3-D) deep-trench capacitor using anti-ferroelectric (AFE) Hf x Zr 1-x O 2 (HZO) is experimentally demonstrated as a promising option for embedded dynamic random-access memory (eDRAM) by showing (i) a successful 10ns polarization switching for read/write operations, (ii) maximum operating voltage less than 1.8V, (iii) retention much longer than 1ms, and (iv) endurance reaching 1012 cycles at elevated temperature. Polarization-voltage (P-V) characteristics and endurance behavior in AFE HZO capacitors are explored through both modeling and P-V evolution during field cycling under extensive pulsing schemes. It is shown that (i) defect diffusion driven by depolarization and (ii) partial domain switching play important roles in endurance fatigue. Finally, a vertical stack with multiple HZO capacitors in parallel is demonstrated, showing a 1T- multi-C memory architecture as a viable path toward future ultra-high density eDRAM technology.

Stacked thin-film transistor based embedded dynamic random-access memory

Abstract: Described herein are arrays of embedded dynamic random-access memory (eDRAM) cells that use TFTs as selector transistors. When at least some selector transistors are implemented as TFTs, different eDRAM cells may be provided in different layers above a substrate, enabling a stacked architecture. An example stacked TFT based eDRAM includes one or more memory cells provided in a first layer over a substrate and one or more memory cells provided in a second layer, above the first layer, where at least the memory cells in the second layer, but preferably the memory cells in both the first and second layers, use TFTs as selector transistors. Stacked TFT based eDRAM allows increasing density of memory cells in a memory array having a given footprint area, or, conversely, reducing the footprint area of the memory array with a given memory cell density.

Self-aligned contacts for thin film transistors

Abstract: Embodiments herein describe techniques for a semiconductor device, which may include a substrate, and a U-shaped channel above the substrate. The U-shaped channel may include a channel bottom, a first channel wall and a second channel wall parallel to each other, a source area, and a drain area. A gate dielectric layer may be above the substrate and in contact with the channel bottom. A gate electrode may be above the substrate and in contact with the gate dielectric layer. A source electrode may be coupled to the source area, and a drain electrode may be coupled to the drain area. Other embodiments may be described and/or claimed.

Capacitor separations in dielectric layers

Abstract: Embodiments herein describe techniques for a semiconductor device including a substrate, a first inter-level dielectric (ILD) layer above the substrate, and a second ILD layer above the first ILD layer. A first capacitor and a second capacitor are formed within the first ILD layer and the second ILD layer. A first top plate of the first capacitor and a second top plate of the second capacitor are formed at a boundary between the first ILD layer and the second ILD layer. The first capacitor and the second capacitor are separated by a dielectric area in the first ILD layer. The dielectric area includes a first dielectric area that is coplanar with the first top plate or the second top plate, and a second dielectric area above the first dielectric area and to separate the first top plate and the second top plate. Other embodiments may be described and/or claimed.

Channel layer formation for iii-v metal-oxide-semiconductor field effect transistors (mosfets)

Abstract: Embodiments herein describe techniques, systems, and method for a semiconductor device. A semiconductor device may include isolation areas above a substrate to form a trench between the isolation areas. A first buffer layer is over the substrate, in contact with the substrate, and within the trench. A second buffer layer is within the trench over the first buffer layer, and in contact with the first buffer layer. A channel area is above the first buffer layer, above a portion of the second buffer layer that are below a source area or a drain area, and without being vertically above a portion of the second buffer layer. In addition, the source area or the drain area is above the second buffer layer, in contact with the second buffer layer, and adjacent to the channel area. Other embodiments may be described and/or claimed.

Transistor device with variously conformal gate dielectric layers

Abstract: Techniques and mechanisms to provide electrical insulation between a gate and a channel region of a non-planar circuit device. In an embodiment, the gate structure, and insulation spacers at opposite respective sides of the gate structure, each extend over a semiconductor fin structure. In a region between the insulation spacers, a first dielectric layer extends conformally over the fin, and a second dielectric layer adjoins and extends conformally over the first dielectric layer. A third dielectric layer, adjoining the second dielectric layer and the insulation spacers, extends under the gate structure. Of the first, second and third dielectric layers, the third dielectric layer is conformal to respective sidewalls of the insulation spacers. In another embodiment, the second dielectric layer is of dielectric constant which is greater than that of the first dielectric layer, and equal to or less than that of the third dielectric layer.

Contact stacks to reduce hydrogen in thin film transistor

Abstract: Embodiments herein describe techniques for a semiconductor device including a substrate and a transistor above the substrate. The transistor includes a channel layer above the substrate, a conductive contact stack above the substrate and in contact with the channel layer, and a gate electrode separated from the channel layer by a gate dielectric layer. The conductive contact stack may be a drain electrode or a source electrode. In detail, the conductive contact stack includes at least a metal layer, and at least a metal sealant layer to reduce hydrogen diffused into the channel layer through the conductive contact stack. Other embodiments may be described and/or claimed.

Contact electrodes and dielectric structures for thin film transistors

Abstract: Embodiments herein describe techniques for a transistor above the substrate. The transistor includes a first gate dielectric layer with a first gate dielectric material above a gate electrode, and a second dielectric layer with a second dielectric material above a portion of the first gate dielectric layer. A first portion of a channel layer overlaps with only the first gate dielectric layer, while a second portion of the channel layer overlaps with the first gate dielectric layer and the second dielectric layer. A first portion of a contact electrode overlaps with the first portion of the channel layer, and overlaps with only the first gate dielectric layer, while a second portion of the contact electrode overlaps with the second portion of the channel layer, and overlaps with the first gate dielectric layer and the second dielectric layer. Other embodiments may be described and/or claimed.

Stacked transistor architecture including nanowire or nanoribbon thin film transistors

Abstract: Stacked transistor structures including one or more thin film transistor (TFT) material nanowire or nanoribbon channel regions and methods of forming same are disclosed. In an embodiment, a second transistor structure has a TFT material nanowire or nanoribbon stacked on a first transistor structure which also includes nanowires or nanoribbons comprising TFT material or group IV semiconductor. The top and bottom channel regions may be configured the same or differently, with respect to shape and/or semiconductor materials. Top and bottom transistor structures (e.g., NMOS/PMOS) may be formed using the top and bottom channel region structures. An insulator region may be interposed between the upper and lower channel regions.

Epitaxial layer with substantially parallel sides

Abstract: Embodiments herein relate to systems, apparatuses, or processes directed to manufacturing transistors that include a substrate, an epitaxial layer (220) with a first side and a second side (228, 230) opposite the first side, where the first side and the second side of the epitaxial layer are substantially planar, where the second side of the epitaxial layer is substantially parallel to the first side, and where the first side of the epitaxial layer is directly coupled with a side of the substrate. In particular, the epitaxial layer may be adjacent to an oxide layer (214) having a side that is substantially planar, where the second side of the epitaxial layer is adjacent to the side of the oxide layer, and the epitaxial layer was grown and the growth was constrained by the oxide layer.

Ferroelectric or anti-ferroelectric trench capacitor with spacers for sidewall strain engineering

Abstract: Ferroelectric or antiferroelectric trench capacitors with spacers for sidewall strain engineering are provided. Described is a ferroelectric-based capacitor that improves reliability of a ferroelectric memory by providing tensile stress along a plane (e.g., x-axis) of a ferroelectric or anti-ferroelectric material of the ferroelectric/anti-ferroelectric based capacitor. Tensile stress is providedby a spacer comprising metal, semimetal, or oxide (e.g., metal or oxide of one or more of: Al, Ti, Hf, Si, Ir, or N). The tensile stress provides polar orthorhombic phase to the ferroelectric materialand tetragonal phase to the anti-ferroelectric material. As such, memory window and reliability of the ferroelectric/anti-ferroelectric oxide thin film improves.

Reducing band-to-band tunneling in semiconductor devices

Abstract: Integrated circuit transistor structures are disclosed that reduce band-to-band tunneling between the channel region and the source/drain region of the transistor, without adversely increasing the extrinsic resistance of the device. In an example embodiment, the structure includes one or more spacer configured to separate the source and/or drain from the channel region. The spacer(s) regions comprise a semiconductor material that provides a relatively high conduction band offset (CBO) and a relatively low valence band offset (VBO) for PMOS devices, and a relatively high VBO and a relatively low CBO for NMOS devices. In some cases, the spacer includes silicon, germanium, and carbon (e.g., for devices having germanium channel). The proportions may be at least 10% silicon by atomic percentage, at least 85% germanium by atomic percentage, and at least 1% carbon by atomic percentage. Other embodiments are implemented with III-V materials.

Ultra-dense ferroelectric memory with self-aligned patterning

Abstract: Described is an ultra-dense ferroelectric memory. The memory is fabricated using a patterning method by that applies atomic layer deposition with selective dry and/or wet etch to increase memory density at a given via opening. A ferroelectric capacitor in one example comprises: a first structure (e.g., first electrode) comprising metal; a second structure (e.g., a second electrode) comprising metal; and a third structure comprising ferroelectric material, wherein the third structure is between and adjacent to the first and second structures, wherein a portion of the third structure is interdigitated with the first and second structures to increase surface area of the third structure. The increased surface area allows for higher memory density.

Capacitor with epitaxial strain engineering

Abstract: Described is a ferroelectric based capacitor that reduces non-polar monoclinic phase and increases polar orthorhombic phase by epitaxial strain engineering in the oxide thin film and/or electrodes. As such, both memory window and reliability are improved. The capacitor comprises: a first structure comprising metal, wherein the first structure has a first lattice constant; a second structure comprising metal, wherein the second structure has a second lattice constant; and a third structure comprising ferroelectric material (e.g., oxide of Hf or Zr), wherein the third structure is between and adjacent to the first and second structures, wherein the third structure has a third lattice constant, and wherein the first and second lattice constants are smaller than the third lattice constant.

Recessed gate oxide on the sidewall of gate trench

Abstract: Described is a transistor, preferably a FinFET or a nanowire FET, which includes: a source region (106); a drain region (108); and a gate region (105, 109) between the source and drain regions, wherein the gate region comprises: high-K dielectric material (105)m which may comprise a ferroelectric material, between spacers (107a, b) such that the high-K dielectric material is recessed; and metal electrode (109) on the recessed high-K dielectric material. The high-k dielectric material (105, 305, 325) may form a convex or a concave interface with the gate metal (109). The gate recessed gate dielectric allows for using thick gate dielectric even with much advanced process technology nodes (e.g., 7 nm and below).

Air gaps and capacitors in dielectric layers

Abstract: Embodiments herein describe techniques for a semiconductor device including a substrate, a first inter-level dielectric (ILD) layer above the substrate, and a second ILD layer above the first ILD layer. The semiconductor device further includes a capacitor having a bottom plate above the substrate, a capacitor dielectric layer adjacent to and above the bottom plate, and a top plate adjacent to and above the capacitor dielectric layer. The bottom plate, the capacitor dielectric layer, and the top plate are within the first ILD layer or the second ILD layer. Furthermore, an air gap is formed next to the top plate and below a top surface of the second ILD layer. Other embodiments may be described and/or claimed.

High-electron-mobility transistors with heterojunction dopant diffusion barrier and devices including integrated circuitry

Abstract: III-V compound semiconductor devices, such transistors, may be formed in active regions of a III-V semiconductor material disposed over a silicon substrate. A heterojunction between an active region of III-V semiconductor and the substrate provides a diffusion barrier retarding diffusion of silicon from the substrate into III-V semiconductor material where the silicon might otherwise behave as an electrically active amphoteric contaminate. In some embodiments, the heterojunction is provided within a base portion of a sub-fin disposed between the substrate and a fin containing a transistor channel region. The heterojunction positioned closer to the substrate than active fin region ensures thermal diffusion of silicon atoms is contained away from the active region of a III-V finFET.

Subfin leakage suppression using fixed charge

Abstract: Disclosed herein are tri-gate transistor arrangements, and related methods and devices. For example, in some embodiments, a transistor arrangement may include a fin stack shaped as a fin extending away from a base, and a subfin dielectric stack. The fin includes a subfin portion and a channel portion, the subfin portion being closer to the base than the channel portion. The subfin dielectric stack includes a transistor dielectric material, and a fixed charge liner material disposed between the transistor dielectric material and the subfin portion of the fin.

Dielectric lining layers for semiconductor devices

Abstract: Solid-state assemblies including dielectric lining layers having localized charges are provided. Processes to form the solid-state assemblies also are provided. The solid-state assemblies can included in CMOS transistors, where first dielectric lining layers having localized charges of positive polarity can be adjacent to the PMOS member and a second dielectric lining layers having localized charges of positive polarity can be adjacent to an NMOS member. The first dielectric lining layers can be adjacent to a first gate electrode of the CMOS transistor, and the second dielectric lining can be adjacent to a second gate electrode of the CMOS transistor. The first dielectric lining layers and the second dielectric lining layers can improve, at least in part, the performance of the CMOS transistor by attracting mobile carriers into respective transport channels of the PMOS member and the NMOS member.

Stacked transistors having device strata with different channel widths

Abstract: Disclosed herein are stacked transistors having device strata (130-1, 130-2) with different channel widths (136-1, 136-2), as well as related methods and devices. In some embodiments, an integrated circuit structure (100) may include stacked strata of transistors, wherein different channel materials (106-1, 106-2) of different strata have different widths.

Stacked transistor layout

Abstract: An apparatus is provided which comprises: a first transistor body comprising one or more semiconductor materials and having a length comprising a source region and a drain region with a channel region therebetween, a first dielectric layer over the first transistor body, a second transistor body comprising one or more semiconductor materials and having a length comprising a source region and a drain region with a channel region therebetween, wherein the second transistor body is over the first dielectric layer and wherein the length of the second transistor body is non-parallel to the length of the first transistor body, and a gate coupled with the channel regions of both the first transistor body and the second transistor body. Other embodiments are also disclosed and claimed.

Stacked-substrate dram semiconductor devices

Abstract: A DRAM integrated circuit device is described in which at least some of the peripheral circuits associated with the memory arrays are provided on a first substrate. The memory arrays are provided on a second substrate stacked on the first substrate, thus forming a DRAM integrated circuit device on a stacked-substrate assembly. Vias that electrically connect the memory arrays on the second substrate to the peripheral circuits on the first substrate are fabricated using high aspect ratio via fabrication techniques.

Forming an oxide volume within a fin

Abstract: Embodiments of the present disclosure may generally relate to systems, apparatus, and/or processes to form volumes of oxide within a fin, such as a Si fin. In embodiments, this may be accomplished by applying a catalytic oxidant material on a side of a fin and then annealing to form a volume of oxide. In embodiments, this may be accomplished by using a plasma implant technique or a beam-line implant technique to introduce oxygen ions into an area of the fin and then annealing to form a volume of oxide. Processes described here may be used manufacture a transistor, a stacked transistor, or a three-dimensional (3-D) monolithic stacked transistor.

Doped sti to reduce source/drain diffusion for germanium nmos transistors

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 STI is doped with an n-type impurity, in regions of the STI adjacent to the source and/or drain regions, to provide dopant diffusion reduction. In some embodiments, the STI region is doped with an n-type impurity including Phosphorous in a concentration between 1 and 10% by atomic percentage. In some embodiments, the thickness of the doped STI region may range between 10 and 100 nanometers.

Two transistor memory cell using stacked thin-film transistors

Abstract: Described herein are two transistor (2T) memory cells that use TFTs as access and gain transistors. When one or both transistors of a 2T memory cell are implemented as TFTs, these transistors may be provided in different layers above a substrate, enabling a stacked architecture. An example 2T memory cell includes an access TFT provided in a first layer over a substrate, and a gain TFT provided in a second layer over the substrate, the first layer being between the substrate and the second layer (i.e., the gain TFT is stacked in a layer above the access TFT). Stacked TFT based 2T memory cells allow increasing density of memory cells in a memory array having a given footprint area, or, conversely, reducing the footprint area of the memory array with a given memory cell density.

Non-selective epitaxial source/drain deposition to reduce dopant diffusion for germanium nmos transistors

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.

Structures and methods for memory cells

Abstract: Disclosed herein are memory cells and memory arrays, as well as related methods and devices. For example, in some embodiments, a memory device may include: a support having a surface; and a three-dimensional array of memory cells on the surface of the support, wherein individual memory cells include a transistor and a capacitor, and a channel of the transistor in an individual memory cell is oriented parallel to the surface.