Contact Resistance Engineering in Graphene Field Effect Transistors

Abstract

As silicon approaches its scaling limits, it becomes increasingly important to explore the usage of alternative materials in field effect transistors (FETs). One such promising material is graphene, bringing to the table great electrical properties such as high intrinsic electron and hole mobilities and saturation velocity. However, despite these excellent properties, graphene FETs are far from reaching their intrinsic performance, in part due to the high contact resistance (RC) observed at the metal-graphene interface. This high RC suppresses on-current, limits the carrier mobility as well as the cutoff frequency. Therefore, in order to continue the development of this technology it is crucial to decrease RC in GFETs. In this study, we have explored the usage of HCl and HNO3 as chemical dopants in the contact regions of GFETs and have demonstrated that such treatments cause a reduction in RC relative to untreated samples. Further, we investigated the mechanism by which these two dopants work to explain the difference in results between the sample sets.