Electro-thermal RF modeling and performance analysis of graphene nanoribbon interconnects

This paper presents an electro-thermal radio frequency (RF) model and performance analysis for multilayer graphene nanoribbon (MLGNR) interconnects. The number of conduction channels is calculated as a function of temperature and Fermi energy. A comprehensive model is developed to calculate the temperature dependent effective mean free path (MFP) considering different scattering mechanisms. The RF model of doped and undoped metallic top-contact (TC), as well as side-contact (SC) MLGNR interconnects is demonstrated using ABCD parameter based multi-conductor transmission line formalism. The RF performance of arsenic pentafluoride (\(\text {AsF}_5\)), lithium (Li) and ferric chloride (\(\text {FeCl}_3\)) intercalation doped TC-MLGNR interconnects is investigated and compared with pristine (undoped) TC and SC-MLGNR interconnects for different temperatures. For the first time, our investigation shows that the electro-thermal RF performance of TC-MLGNR can be improved by intercalation doping. It is found that \(\text {AsF}_5\), Li and \(\text {FeCl}_3\) intercalated top-contact MLGNR can operate up to a few GHz for semi-global interconnects (\(100\,\upmu \)m) and several MHz for global interconnects (\(500\,\upmu \)m). Our analysis also proves that the Li intercalated TC-MLGNR shows the best RF performance as compared to conventional copper, pristine, and other type of intercalation doped TC-MLGNR interconnects over the chip operating temperature range from 233 to 378 K. The performance of Li intercalated TC-MLGNR has been found to be improved further by increasing the specularity during fabrication.