Abstract: Techniques for forming thin film transistors (TFTs) having multilayer and/or concentration gradient semiconductor regions. An example integrated circuit includes a gate electrode, a gate dielectric on the gate electrode, and a semiconductor region on the gate dielectric. In some cases, the semiconductor region includes a plurality of compositionally different material layers, at least two layers of the different material layers each being a semiconductor layer. In some other cases, the semiconductor region includes a single layer having a material concentration gradient extending from a bottom surface of the single layer (adjacent to the gate dielectric) to a top surface of the single layer. The integrated circuit further includes first and second conductive contacts that each contact a respective portion of the semiconductor region.

Abstract: Techniques are provided herein for forming thin film transistor structures having a multilayer and/or concentration gradient gate dielectric. Such a gate dielectric can be used, to tune the performance and/or reliability of the transistor. According to some such embodiments, memory structures having thin film transistor (TFT) structures are arranged in a two-dimensional array within one or more interconnect layers and stacked in a vertical direction such that multiple tiers of memory structure arrays are formed within the interconnect region. Any of the given TFT structures may include a multilayer and/or graded gate dielectric that includes at least two or more different dielectric layers and/or a material concentration gradient through a thickness of the gate dielectric.

Abstract: Techniques are provided herein for forming multi-tier memory structures with graded characteristics across different tiers. A given memory structure includes memory cells, with a given memory cell having an access device and a storage device. The access device may include, for example, a thin film transistor (TFT) structure, and the storage device may include a capacitor. Certain geometric or material parameters of the memory structures can be altered in a graded fashion across any number of tiers to compensate for process effects that occur when fabricating a given tier, which also affect any lower tiers. This may be done to more closely match the performance of the memory arrays across each of the tiers.

Abstract: Described herein are stacked memory devices that include some peripheral devices for controlling the memory in a separate layer from one or more memory arrays. The layers of the memory device are connected together using vias, which transfer power and data between the layers. In some examples, a portion of the peripheral devices are included in a memory layer, and another portion are included in a peripheral device layer. Multiple layers of memory arrays and/or peripheral devices may be included, e.g., one peripheral device layer may control multiple layers of memory arrays, or different layers of memory arrays may have dedicated peripheral device layers. Different types of memory arrays, such as DRAM or SRAM, may be included.

Abstract: Techniques for forming thin film transistors (TFTs) having multilayer contact structures. An example integrated circuit includes a gate electrode, a gate dielectric on the gate electrode, a semiconductor region on the gate dielectric, and a conductive contact that contacts at least a portion of the semiconductor region. In some other cases, the conductive contact comprises a multilayer structure having at least a first material layer on the at least a portion of the semiconductor region, at least a second material layer on the first material layer, and a conductive fill material over the first and second material layers. In some other cases, the conductive contact comprises a multilayer structure having (1) a graded material layer on the at least a portion of the semiconductor region and (2) a conductive fill material over the graded material layer, wherein the graded material layer comprises a concentration gradient of a given element.

Abstract: Described herein are memory cells that include two transistors stacked above one another above a support structure where neither one of the transistors is coupled to a capacitor and where at least one of the two transistors is a thin-film transistor. In such 2T capacitorless memory cells, a first transistor may be referred to a write transistor, and a second transistor may be a read transistor. The first transistor may be a three-terminal device having two S/D terminals and a gate terminal, while the second transistor may be a four-terminal device having two S/D terminals and two gate terminals.

Abstract: Techniques are provided herein for forming thin film transistor structures having co-doped semiconductor regions. The addition of insulating dopants can be used to improve the performance, stability, and reliability of the TFT. A given TFT structure within an array of similar TFT structures formed in an interconnect region may include a semiconductor region that is co-doped with one or more additional elements. The doping profile can be tuned to optimize performance, stability, and reliability of the TFT structure. In some embodiments, the doping profile causes an overall reduction in the conductivity of the semiconductor region, leading to a higher threshold voltage. Designing access devices (in, for example, a DRAM architecture) with higher threshold voltages can be beneficial for improving reliability of the memory cell.

Abstract: IC devices implementing bilayer stacking with lines shared between bottom and top memory layers, and associated systems and methods, are disclosed. An example IC device includes a support structure, a front end of line (FEOL) layer and a back end of line (BEOL) layer. The BEOL layer includes a first memory cell in a first layer over the support structure, an electrically conductive line in a second layer, above the first layer, and a second memory cell in a third layer, above the second layer. The line could be one of a wordline, a bitline, or a plateline that is shared between the first and second memory cells. In particular, bilayer stacking line sharing is such that only one line is provided as a line to be shared between one or more of the memory cells of the first layer and one or more memory cells of the third layer.

Abstract: Techniques are provided for making asymmetric contacts to improve the performance of thin film transistors (TFT) structures. The asymmetry may be with respect to the area of contact interface with the semiconductor region and/or the depth to which the contacts extend into the semiconductor region. According to some embodiments, the TFT structures are used in memory structures arranged in a two-dimensional array within one or more interconnect layers and stacked in a vertical direction such that multiple tiers of memory structure arrays are formed within the interconnect region. Any of the given TFT structures may include asymmetric contacts, such as two contacts that each have a different contact area to a semiconductor region, and/or that extend to different depths within the semiconductor region. The degree of asymmetry may be tuned during fabrication to modulate certain transistor parameters such as, for example, leakage, capacitance, gate control, channel length, or contact resistance.

Abstract: Techniques are provided for forming one or more thermoelectric devices integrated within a substrate of an integrated circuit. Backside substrate processing may be used to form adjacent portions of the substrate that are doped with alternating dopant types (e.g., n-type dopants alternating with p-type dopants). The substrate can then be etched to form pillars of the various n-type and p-type portions. Adjacent pillars of opposite dopant type can be electrically connected together via a conductive layer. Additionally, the top portions of adjacent pillars are connected together, and the bottom portions of a next pair of adjacent pillars being coupled together, in a repeating pattern to ensure that current flows through the length of each of the doped pillars. The flow of current through alternating n-type and p-type doped material creates a heat flux that transfers heat from one end of the integrated thermoelectric device to the other end.

Abstract: Described herein are transistor devices formed using perovskite gate dielectrics. In one example, a transistor includes a high-k perovskite dielectric material between a gate electrode and a thin film semiconductor channel. In another example, four-terminal transistor includes a semiconductor channel, a gate stack that includes a perovskite dielectric layer on one side of the channel, and a body electrode on an opposite side of the channel. The body electrode adjusts a threshold voltage of the transistor.

Abstract: Techniques are provided herein for forming backend memory structures with airgaps in an interconnect region above semiconductor devices. The airgaps may be provided between conductive features, such as wordlines, to reduce parasitic capacitance. An interconnect region above a plurality of semiconductor devices includes any number of interconnect layers. A first interconnect layer includes first conductive layers (e.g., wordlines) extending in a first direction with airgaps between adjacent first conductive layers. A second interconnect layer over the first interconnect layer includes at least portions of memory cells over corresponding first conductive layers. A third interconnect layer over the second interconnect layer includes a second conductive layer (e.g., bitline) extending in a second direction over one or more of the at least portions of memory cells.

Abstract: Disclosed herein are transistors with ferroelectric gates, and related methods and devices. For example, in some embodiments, a transistor may include a channel material, and a gate stack, and the gate stack may include a gate electrode material and a ferroelectric material between the gate electrode material and the channel material.

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.

Abstract: Disclosed herein are transistor electrode-channel arrangements, and related methods and devices. For example, in some embodiments, a transistor electrode-channel arrangement may include a channel material, source/drain electrodes provided over the channel material, and a sealant at least partially enclosing one or more of the source/drain electrodes, wherein the sealant includes one or more metallic conductive materials.

Abstract: Embodiments of the present disclosure provide power to backend memory of an IC device from the back side of the device. An example IC device with back-side power delivery for backend memory includes a frontend layer with a plurality of frontend components such as frontend transistors, a backend layer (that may include a plurality of layers) with backend memory (e.g., with one or more eDRAM arrays), and a back-side power delivery structure with a plurality of back-side interconnects electrically coupled to the backend memory, where the frontend layer is between the back-side power delivery structure and the backend layer.

Abstract: Top-gate thin film transistor (TFTs) structures. Thin film transistors when in the top-gate configuration suffer from contact resistance. An example TFT includes a semiconductor layer doped with one or more dopant elements. A gate dielectric layer is on the semiconductor layer, and a gate electrode is on the gate dielectric layer. The semiconductor layer is doped with the one or more dopant elements beneath the gate dielectric layer. The TFT may further include one or more contacts and/or one or more gate spacers, and the semiconductor layer may further be doped with the one or more dopant elements beneath the contact(s) and/or gate spacer(s).

Abstract: Thin film transistors are described. An integrated circuit structure includes a gate electrode. A gate dielectric layer is on the gate electrode. A channel material layer is on the gate dielectric layer. Source or drain contacts are on the channel material layer. Each of the source or drain contacts has sidewalls which taper outwardly from a top of the source or drain contact to a bottom of the source or drain contact.

Abstract: Thin film transistors are described. An integrated circuit structure includes a gate electrode. A gate dielectric layer is on the gate electrode. A channel material layer is on the gate dielectric layer. A dielectric layer is over the channel material layer. Source or drain contacts are on the channel material layer. Each of the source or drain contacts includes a semiconductor material layer, a conductive liner within the semiconductor material layer, and a conductive fill within the conductive liner. One, two or all three of the semiconductor material layer, the conductive liner, or the conductive fill has an uppermost surface below an uppermost surface of the dielectric layer.

Abstract: Thin film transistors are described. An integrated circuit structure includes a gate electrode. A gate dielectric layer is on the gate electrode. A channel material layer is on the gate dielectric layer. Source or drain contacts are on the channel material layer. Each of the source or drain contacts has a first sidewall in contact with a dielectric backbone, and a second sidewall in contact with an insulating material having a composition different than the dielectric backbone.