The present disclosure relates to a semiconductor device and a manufacturing method, and more particularly to a semiconductor interconnect structure incorporating a graphene barrier layer. The present disclosure provides a method of forming a graphene barrier layer on select surfaces using a self-assembly monolayer (SAM). The SAM layer can be selectively formed on dielectric surfaces and annealed to form thin graphene barrier layers. The thickness of the graphene barrier layers can be selected by choosing different alkyl groups of the SAM layer.