Characterization of Al2O3 gate dielectric for graphene electronics on flexible substrates

Paper in proceeding, 2016

In this work, we have fabricated parallel-plate capacitor test structures consisting of 35 nm thick Al2O3 dielectric film and graphene as bottom electrode on polyethylene terephthalate (PET) to characterize the electrical properties of the dielectric film for graphene electronics on flexible substrates.It was found out that leakage current density in the Al2O3 film is less than 0.1 mA/cm2 at 5 V, which allows for applying it as a gate dielectric in graphene-based field effect transistors (GFETs) on flexible substrates. Dielectric constant of the Al2O3 film is approx. 7.6, which is close to the bulk value and confirms good quality of the Al2O3 film. Analysis indicates that the measured loss tangent, which is up to 0.2, is governed mainly by the dielectric loss in the Al2O3 and can be associated with defects in Al2O3 and Al2O3/graphene interface. Our results will be used in further development of GFETs on flexible substrates.