Impact of GFETs geometries on RF performances

Graphene is a relatively new material whose unique properties have attracted significant interest for its use in electronic and photonic applications. In particular, field effect has been proved in graphene samples and the observed high carrier mobility makes graphene an interesting solution for high frequency electronics. In this work, we focused on the analysis of microwave parameters dependence on geometries in Graphene Field Effect Transistors (GFETs). In particular, a statistical, experimental investigation of the cut-off frequency (fT) and of the output impedance (Zout) dependency on both the gate-drain/source distance (Δ) and the gate length (Lg) was carried out. 24 GFET families were fabricated on the same chip, each one made of 10 identical (same geometry) devices. The analysis of the measured data shows that fT and Zout are both Δ and Lg dependent, and that there exists a region in Δ and Lg design space where fT is optimized.