Improving consistency and performance of graphene-based devices via Al sacrificial layer

Graphene has attracted much attention because of its excellent physical properties and great potential applications in electronic devices. However, traditional lithography process using photoresist masks will inevitably leave some organic matter on the graphene surface, which will reduce the performance and yield of graphene-based devices. In this paper, a new lithography process for the separation of graphene and photoresist using Al sacrificial layer is proposed. ToF-SIMS demonstrated that the process not only avoids photoresist residues, but also significantly reduces PMMA contamination without introducing Al atomic residues. The morphology also shows that the graphene pattern prepared by this process is flatter and cleaner. More importantly, electrical tests show that Al sacrificial layer process can significantly improve the consistency of the resistance (standard deviation reduced by 41.9%) and the sensitivity of the device (temperature sensor sensitivity increased by 54.41%). This work provides a way for the commercial application of graphene electronic devices.