Processing-induced strain in dual-gated graphene FETs

Dual-gated graphene field-effect transistors (FETs) are subject to stress from the top and back gate oxides, as well as the contacts. This stress alters the electronic structure of graphene. We report a study on the role of different processing steps in inducing strain in the channel of graphene FETs. We use Raman analysis to study the processing-induced strain during the fabrication of dual-gated graphene FETs. We find that the ALD seed layer evaporation induces significant tensile strain in the graphene channel, while the ALD process itself significantly relieves the tensile strain induced by the evaporated seed layer.