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In this paper, lateral gate-all-around nano-sheet transistors (NSH-FETs) are explored from intrinsic performance to dc and ring oscillator (RO) benchmark compared with FinFETs and nanowire transistors (NW-FETs) for sub-7-nm node. The band structure calculated technology computer aided design results show comparable intrinsic performance to FinFETs at same channel cross section. On top of that, dc and RO are evaluated by taking into account electrostatics, parasitic components, and layout configurations. The NSH-FETs show an advantage in drive current with the NSH width but their RO performance is limited by the device capacitance. The multiple narrow NSH-FET shows ~5% higher drive current compared to the NW-FET at similar subthreshold swing, allowing heavier capacitive loaded circuit. In addition, NSH-FETs can provide the device design freedom from aggressive fin pitch scaling. [ABSTRACT FROM PUBLISHER]

We investigate the impact of wire geometry on the resistance, capacitance, and RC delay of Cu/low- $k$ damascene interconnects for fixed line-to-line pitch. The resistance is computed by applying a semiempirical resistivity model, calibrated to Cu damascene wires, integrated with a Ru-based liner, currently investigated for the 7 nm logic technology node. The capacitance is simulated by means of a 2D field solver (Raphael) by Synopsys. The impact of line dimensions is analyzed for the case of 32 nm pitch interconnects, which are representative of the 7 nm logic technology node. We show that for aspect ratios greater than 1, the resistance is more sensitive to variations of the line width rather than of the line height, because of the higher surface scattering induced by the sidewall interfaces, which are closer to each other compared with the top and bottom interfaces. For capacitance, low- $k$ sidewall damage exacerbates capacitance sensitivity to line dimensions and, for typical interconnect schemes, the impact of line width variations dominates over variations of the line height. We demonstrate that for a given pitch and dielectric stack height, the RC delay can be significantly reduced by targeting wider and deeper damascene trenches, that is, by trading capacitance for resistance, and that an optimal wire geometry for RC delay minimization exists. In addition, we show that a given RC delay can be achieved with several geometries and, therefore, $R$ and $C$ pairs, which represents a useful degree of freedom for designers to optimize system-level performance. As an application, we analyze a possible 7 nm technology scenario and show that wide and deep damascene trenches can mitigate the impact of the increased wire resistance on circuit delay. [ABSTRACT FROM AUTHOR]

In this paper, we benchmark the performance of monolayer and bilayer MoS2 FETs (MFETs) against various multigate (MuG) Si-FET options, such as FinFETs and lateral and vertical nanowire FETs, for a 5-nm node and beyond. We compare the performance metrics of all the device options at the ring-oscillator (RO) level, accounting for not only intrinsic and extrinsic parasitic elements but also interconnects. Using the atomistic two-band ballistic quantum transport simulations, we evaluate ON-current and intrinsic capacitances for MoS2-based devices. Furthermore, we calibrate two-band model currents with more sophisticated full-band diffusive simulations to obtain realistic performance metrics at the circuit level. We show that both the intrinsic and parasitic capacitances of a single-gate MFET are lesser than those of a double-gate (DG) MFET, resulting in 13% lesser energy consumption. A DG bilayer (DGBL) MFET shows the best performance among different MFETs. In comparison toMuG FETs, the DGBL MFET offers not only lower energy consumption but also 35%–45% lower speed. In the end, to meet the target performance, we evaluate the impact of the device current, contact resistance, and back-end-of-the-line load on the speed of RO with the DGBL MFET. [ABSTRACT FROM PUBLISHER]

For sub-7-nm technology nodes, the gate-all-around (GAA) nanowire-based device structure is a strong candidate to sustain scaling according to Moore’s Law. For the first time, the performance of two GAA device options—lateral FET (LFET) and vertical FET (VFET)—is benchmarked and analyzed at the system level using an ARM core processor, based on realistic compact device models at the 5-nm technology node. Tradeoffs among energy, frequency, leakage, and area are evaluated by a multi- Vth optimization flow. A variety of relevant device configurations, including various number of fins, nanowires, and nanowire stacks, are explored. The results demonstrate that an LFET GAA core has a larger maximum frequency than its VFET counterpart because the channel stress that can be created in the LFETs results in a larger ON current. For fast timing targets, the LFET cores are therefore superior. However, for slow timing targets (e.g., 5 ns), the VFET cores with three nanowires offer a 7% area reduction and a 20% energy saving compared with the LFET cores with 2fin/2stack at the same leakage power. [ABSTRACT FROM PUBLISHER]

For the first time, we present complete device threshold voltage (VT)-targeting methodology for FinFET SRAM in 10-nm technology, considering capacitance due to metal pattering and device variability to set target read current for different variants of SRAM architecture to determine technology high-density (HD) SRAM cell. The VT-targeting methodology brings into play the worst case read and write margins available for SRAM cell to determine nominal device VT by tuning the work function of metal gate. Analysis shows that for minimum leakage current, 112 SRAM cell is optimum, whereas for the same area of 0.0546~\mu \mathrm{m}^{\mathrm {2}} with 50% higher leakage, 122 SRAM outperform by 5% and 20% improved read and write margins, respectively. The 122 SRAM as HD cell reduces the cost of the technology by sharing P-channel field effect transistor (PFET) and N-channel field effect transistor (NFET) VT mask with the high threshold voltage logic devices, whereas the 112 SRAM device shares only NFET VT mask. The 111 SRAM can achieve target performance at lesser area of 0.048~\mu \mathrmm^\mathrm 2 by compromising read stability, which will result in lower yield. At 64-nm pitch, litho-etch litho-etch (LELE) double-patterned gate impacts device performance and alleviates variability; hence the read margin of SRAM cell should consider an additional 1\sigma \mathrm {\mathbf {rsnm}} margin to retain the same yield in 10-nm-technology era. [ABSTRACT FROM AUTHOR]

Based on realistic circuit- and system-level simulations, graphene interconnects are analyzed in terms of multiple material properties, such as the mean free path (MFP), the contact resistance, and the edge roughness. The benchmarking results indicate that the advantage of using graphene interconnects occurs only under certain circumstances. The device-level parameters, including the supply and threshold voltages, and the circuit-level parameters, including the wire length and width, have large impacts on both the delay and energy-delay product (EDP). At the circuit level, one representative circuit, a 32-bit adder, is investigated, where up to 40% and 70% improvements in delay and EDP are observed. At the system-level analysis, an ARM Cortex-M0 processor is synthesized, and placement and routing are performed. After replacing copper interconnects with multilayer graphene interconnects, up to 15% and 22% performance improvements in clock frequency and EDP have been observed. It is also demonstrated that the benefits of using graphene for the ARM core processor are strongly dependent on the quality of the graphene, such as the MFP and the edge roughness. [ABSTRACT FROM AUTHOR]

In this paper, we compare the performances of FinFETs, lateral gate-all-around (GAA) FETs, and vertical GAAFETs (VFETs) at 7-nm node dimensions and beyond. Comparison is done at ring oscillator level accounting not only for front-end of line devices but also for interconnects. It is demonstrated that FinFETs fail to maintain the performance at scaled dimensions, while VFETs demonstrate good scalability and eventually outperform lateral devices both in speed and power consumption. Lateral GAAFETs show better scalability with respect to FinFETs but still consume 35% more energy per switch than VFETs if made under 5-nm node design rules. [ABSTRACT FROM AUTHOR]

This paper describes the implications of bias temperature instability (BTI)-induced time-dependent threshold voltage distributions on the performance and yield estimation of digital circuits. The statistical distributions encompassing both time-zero and time-dependent variability and their correlations are discussed. The impact of using normally distributed threshold voltages, imposed by state-of-the-art design approaches, is contrasted with our defect-centric approach. Extensive Monte Carlo simulation results are shown for static random access memory cell and ring oscillator structures. [ABSTRACT FROM PUBLISHER]