Electrical transport characteristics of atomic contact and nanogap dynamically formed by electromigration

Abstract

The feature size of circuits was gradually reduced to a few nanometers, which is prone to lead to the failure of the metal circuit even upon a low bias voltage due to the electromigration. Therefore, it is essential to understand the electrical transport characteristics of a narrow metal wire shrunk to atomic scale due to electromigration. To this end, we report that the approach for metal deposition and the underneath substrate play a critical role in determining the electron transport behavior. It is observed that the conductance of the narrow metal wire fabricated on a SiO2 substrate first rises and then decreases during the electromigration process when the cross section of the metal wire is reduced to a few atoms. However, such a phenomenon is not observed for the metal wire fabricated on a polyimide substrate. Assisted by component analysis technology, it is revealed that the metal atoms can penetrate into the underneath substrate during the metal deposition process, and the metal atoms buried in the different substrates result in distinguished conductance behavior.