摘要
The speed of frequency response of all published carbon nanotube （CNT） integrated circuits （ICs） is far from that predicted. The transient response of CNT ICs is explored systematically through the combination of experimental and simulation methods. Complementary field-effect-transistor （FET） based inverters were fabricated on a single semiconducting CNT, and the dynamic response measurement indicates that it can only work at an unexpectedly low speed, i.e. with a large propagation delay of 30 }_ts. Owing to the larger output resistance of CNT FETs, the existence of parasitic capacitances should induce much larger resistive-capacitive （RC） delay than that in Si ICs. Through detailed analysis combining simulation and experimental measurements, several kinds of parasitic capacitances dragging down the actual speed of CNT FET ICs are identified one by one, and each of them limits the speed at different levels through RC delay. It is found that the parasitic capacitance from the measurement system is the dominant one, and the large RC delay lowers the speed of CNT FETs logic circuits to only several kHz which is similar to the experimental results. Various optimized schemes are suggested and demonstrated to minimize the effect of parasitic capacitances, and thus improve the speed of CNT ICs.
所有的频率反应的速度出版了碳 nanotube (CNT ) 集成电路(IC ) 远离那被预言。CNT IC 的短暂反应通过联合系统地被探索试验性并且模拟方法。互补 field-effect-transistor (联邦货物税) 基于 inverters 在单个半导体的 CNT 上被制作，并且动态反应测量显示它能仅仅以出人意料地低的速度工作，即与 30 s 的大繁殖延期。由于 CNT 联邦货物税的更大的产量抵抗，寄生电容的存在应该导致大部分更大抵抗电容(RC ) 在 Si IC 比那推迟。通过联合模拟和试验性的大小的详细分析，在 CNT 联邦货物税 IC 的实际速度下面拖的几种寄生电容一个一个地被识别，并且他们中的每通过 RC 延期在不同层次限制速度。从测量系统的寄生电容是主导的，这被发现，并且大 RC 延期降低 CNT 联邦货物税逻辑电路的速度到仅仅类似于试验性的结果的几 kHz。各种各样的优化计划被建议并且示威了最小化寄生电容的效果，并且因此改进 CNT IC 的速度。
基金
This work was supported by the National Basic Research Program of China （Nos. 2011CB933001 and 2011CB933002）, the National Natural Science Foundation of China （Nos. 61322105, 61271051, 61376126, 61321001 and 61390504）, and the Beijing Municipal Science and Technology Commission （Nos. Z131100003213021 and 20121000102）.
