Ultrafast Bonding of Wafer Scale Vertical Aligned Carbon Nanotubes onto Gold Surface by Induction Heating

Abstract

A room temperature bonding method was developed in this study to bond vertical allied carbon nanotubes (CNTs) onto gold surface within 5 seconds, and the contact electrical resistance between the CNTs and metal surface was reduced by up to 99%. Unlike traditional thermocompression bonding method, the non-contact induction selective heating occurred at CNT/metal interface, avoiding high temperature and pressure applied on the device. In particular, the atomic study indicated that surface charges induced by the induction heating could improve the wetting between metal atoms and the CNT surface. In addition, the contact configure modification effectively facilitated the surface melting due to increased anharmonicity at the interface. As a result, the welding occurred at much lower temperature than the metal melting point. This behavior provides more material choices for targeting metallic surface rather than using metals with excellent wetting properties to the carbon nanotube. Also, the debonding process also showed that the bonding strength was higher than the tensile strength of CNT itself. The process is promising for large-scale and wafer-level CNT-based devices and thermal interface material assembly.