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Carbon-based nanomaterials such as metallic singlewalled carbon nanotubes, multiwalled carbon nanotubes (MWCNTs), and graphene have been considered as some of the most promising candidates for future interconnect technology because of their high current-carrying capacity and conductivity in the nanoscale, and immunity to electromigration, which has been a great challenge for scaling down the traditional copper interconnects. Therefore, studies on the performance and optimization of carbon-based interconnects working in a realistic operational environment are needed in order to advance the technology beyond the exploratory discovery phase. In this paper, we present the first demonstration of graphene interconnects monolithically integrated with industry-standard complementary metal-oxide-semiconductor technology, as well as the first experimental results that compare the performance of high-speed on-chip graphene and MWCNT interconnects. The graphene interconnects operate up to 1.3-GHz frequency, which is a speed that is commensurate with the fastest high-speed processor chips today. A low-swing signaling technique has been applied to improve the speed of carbon interconnects up to 30%.

This paper presents an energy-efficient chemical sensor system that uses carbon nanotubes (CNT) as the sensing medium. The room-temperature operation of CNT sensors eliminates the need for micro hot-plate arrays, which enables the low energy operation of the system. An array of redundant CNT sensors overcomes the reliability issues incurred by the CNT process variation. The sensor interface chip is designed to accomodate a 16-bit dynamic range by adaptively controlling an 8-bit DAC and a 10-bit ADC. A discrete optimization methodology determines the dynamic range of the DAC and the ADC to minimize the energy consumption of the system. A simple calibration technique using off-chip reference resistors reduces the DAC non-linearity. The sensor interface chip is designed in a 0.18m CMOS process and consumes, at maximum, 32 W at 1.83 kS/s conversion rate. The designed interface achieves 1.34% measurement accuracy across the 10 k-9 M range. The functionality of the full system, including CNT sensors, has been successfully demonstrated.

Abstract-This paper presents an energy efficient chemical sensor system that uses carbon nanotubes (CNT) as the sensor. The room-temperature operation of CNT sensors eliminates the need for micro hot-plate arrays, which enables the low energy operation of the system. The sensor interface chip is designed in a 0.18 µm CMOS process and consumes, at maximum, 32 µW at 1.83 kS/s conversion rate. The designed interface achieves 1.34% measurement accuracy over 10 kΩ -9 MΩ dynamic range. The functionality of the full system, including CNT sensors, has been successfully demonstrated.

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