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We propose a path for extending the technology roadmap when currently considered technology boosters (e.g., strain, high-κ/metal gate) reach their limits and physical gate length can no longer be effectively scaled down. By judiciously engineering the device parasitic resistance and parasitic capacitance, and considering the impact of the interconnect wiring capacitance, we propose scenarios of selective device structure scaling that will enable technology scaling and contacted gate pitch scaling for several generations beyond the currently perceived limits. [ABSTRACT FROM AUTHOR]

Carbon-nanotube (CNT) field-effect transistors (CNFETs) are promising extensions to silicon CMOS. Simulations show that CNFET inverters fabricated with a perfect CNFET technology have 13 times better energy delay product compared with 32-nm silicon CMOS inverters. The following two fundamental challenges prevent the fabrication of CNFET circuits with the aforementioned advantages: 1) misaligned and mispositioned CNTs and 2) metallic CNTs. Misaligned and mispositioned CNTs can cause incorrect functionality. This paper presents a technique for designing arbitrary logic functions using CNFET circuits that are guaranteed to implement correct functions even in the presence of a large number of misaligned and mispositioned CNTs. Experimental demonstration of misaligned and mispositioned CNT-immune logic structures is also presented. [ABSTRACT FROM AUTHOR]

This paper presents a complete circuit-compatible compact model for single-walled carbon-nanotube field-effect transistors (CNFETs) as an extension to Part 1 of this two-part paper. For the first time, a universal circuit-compatible CNFET model including the practical device nonidealities is implemented with HSPICE. In addition to the nonidealities included in the companion paper, this paper includes the elastic scattering in the channel region, the resistive source/drain (S/D), the Schottky-barrier resistance, and the parasitic gate capacitances. More than one nanotube per device can be modeled. Compared to silicon technology, the CNFETs show much better device performance based on the intrinsic CV/I gate-delay metric (six times for nFET and 14 times for pFET) than the MOSFET device at the 32-nm node, even with device nonidealities. This large speed improvement is significantly degraded (by a factor of five to eight) by interconnect capacitance in a real circuit environment. We performed circuit-performance comparison with all the standard digital library cells between CMOS random logic and CNFET random logic with HSPICE simulation. Compared to CMOS circuits, the CNFET circuits with one to ten carbon nanotubes per device is about two to ten times faster, the energy consumption per cycle is about seven to two times lower, and the energy-delay product is about 15-20 times lower, considering the realistic layout pattern and the interconnect wiring capacitance. [ABSTRACT FROM AUTHOR]

We propose selective scaling of device footprint for 65 nm and beyond CMOS technologies. The benefits of selective scaling of device footprint are illustrated using an ultrathin-body fully depleted silicon-on-insulator transistor as an example. We study the effect of footprint scaling on device, circuit, and system level performance. A complete 2-D device structure is modeled for the numerical analysis. The results predict that an optimal footprint design can provide 30% smaller chip layout area, 20% faster speed, and 10% less dynamic power on overall chip performance benchmarked with a 53-bit pipelined multiplier. The variability analysis on both dc and ac characteristics indicates that the benefits of selective footprint scaling are not degraded by device variation. [ABSTRACT FROM AUTHOR]

This paper proposes a simple and accurate expression for inverter effective drive current for nanoscale Si and carbon nanotube FET (CNFET) performance benchmarking. The choice of Ieff = (INL + INM + INH - IP)/3, where INL = IDS(N-FET) (VGS = 0.5VDD, VDS = VDD), INM = IDS(N-FET) (VGS = 0.75VDD, VDS = 0.75VDD), INH = IDS(N-FET) (VGS = VDD, VDS = 0.5VDD), and IP = ISD(P-FET) (VSG = 0.25VDD, VSD = 0.25VDD), includes the effects of both the nFET and the pFET of an inverter and accurately captures the inverter delay performance over many CMOS technology nodes and in the presence of device nonidealities. The proposed metric indicates that the performance enhancement of CNFETs over Si MOSFETs is not as large as that predicted by IDSsat in a circuit environment because of the nonideal I-V characteristics. [ABSTRACT FROM AUTHOR]