Carbon nanotube field-effect transistors: Present and future
Abstract
Traditional silicon complementary metal-oxide semiconductor (CMOS) field-effect transistor (FET) technology has been pushed to 14 nm node and was predicted to arrive at its absolute performance limit in the near future. Therefore, a new transistor technology is urgently needed to replace or supplement Si CMOS and to extend Moore’s Law. Owing to its ultra-thin body and ultra-high carrier mobility, carbon nanotube (CNT) has been considered as one of the most promising channel material to replace silicon at post-Moore’s Law era. During the last 20 years, great progresses have been made on carbon nanotube field-effect transistors (CNTFETs) by researchers. In this review paper, we retrospect some key technologies of CNTFET, including carbon nanotube N-type ohmic contact ballistic transistors, doping-free complementary metal-oxide semiconductor (CMOS) technology, self-aligned high κ dielectric top gate geometry and length scaling of CNTFETs, etc. Besides, some challenges on the further development of CNTFETs, such as the preparation of high density and pure semiconducting CNT channel material at large scale and the contact performance during contact length scaling down, are discussed and the possible corresponding solutions are put forward. Based on the results of analysis and simulations, we make projections for the development of CNTFETs, which demonstrate great potential in the future. By effectively optimizing the CNT material quality and the device structure, CNTFETs may strikingly outperform the silicon counterparts at corresponding technology node and become competitive information processing devices at post-Moore’s Law era.
