End-bonded contacts for carbon nanotube transistors with low, size-independent resistance

Abstract

Moving beyond the limits of silicon transistors requires both a high-performance channel and high-quality electrical contacts. Carbon nanotubes provide high-performance channels below 10 nanometers, but as with silicon, the increase in contact resistance with decreasing size becomes a major performance roadblock. We report a single-walled carbon nanotube (SWNT) transistor technology with an end-bonded contact scheme that leads to size-independent contact resistance to overcome the scaling limits of conventional side-bonded or planar contact schemes. A high-performance SWNT transistor was fabricated with a sub-10-nanometer contact length, showing a device resistance below 36 kilohms and on-current above 15 microampere per tube. The p-type end-bonded contact, formed through the reaction of molybdenum with the SWNT to form carbide, also exhibited no Schottky barrier. This strategy promises high-performance SWNT transistors, enabling future ultimately scaled device technologies.

Strong and Broadly Tunable Plasmon Resonances in Thick Films of Aligned Carbon Nanotubes

“…The key to developing these resonators into highperformance infrared-and terahertz-frequency photodetectors will now be engineering the interface from nanotubes to metal contacts. One promising approach would be to anneal refractory metal contacts 39 that form an end-bonded carbide to the thick nanotube film.…”

Resist-free fabricated carbon nanotube field-effect transistors with high-quality atomic-layer-deposited platinum contacts

“…2 Carbon nanotube field-effect transistors (CNTFETs) have been explored as an alternative for over a decade, motivated by superior ballistic transport properties and the ultrathin nature of the carbon nanotube. [3][4][5][6][7] Recent progress in growth, purification, and placement of carbon nanotubes demonstrates that the main hurdles for using carbon nanotubes in semiconductor applications are surpassable. [8][9][10][11][12] However, many challenges for reliable fabrication of CNTFETs still remain.…”

A Survey of Carbon Nanotube Interconnects for Energy Efficient Integrated Circuits

“…This is particularly problematic for vertical interconnects where the bottom electrode acts both as a support for the catalytic growth of CNTs and as an electrical contact [67,119]. Another major roadblock comes from the fact than one ideally desires to inject current alongside the axis of the CNT to create a so-called end-bonded contact to the CNTs, which requires a perfect control over the quality of the interface between open-ended CNTs and metal [68].…”

“…The first successful attempts at defining metal contacts on single CNTs have already been reported in the late 1990s, along with the first experimental studies of their electrical properties [100][101][102]. Today, even though the contacting of single CNTs was demonstrated and nanoscale devices based on CNTs can be built and characterized [103] -the realization of transparent ohmic electrical contacts is still challenging [68].…”