Self-aligned graphene-on-SiC and graphene-on-Si MOSFETs on 75 mm wafers

Graphene has shown the highest carrier Hall mobility of >100,000 cm2/Vs with theoretical saturation velocity (Vsat) and source-injection velocity converging at ∼5E7 cm/sec [1] and ∼6E7 cm/sec, respectively. A potential combination of high current-carrying density, transconductance, and low access resistance could make graphene an attractive candidate for high-performance RF applications. So far, epitaxial graphene MOSFETs [2] in the early stages of development have revealed technical challenges: the current-voltage characteristics are quasi-linear with weak saturation behaviors and low transconductance per gate capacitance (<100 mS/mm). In addition, the Ion/Ioff ratio has been <10. While epitaxial graphene RF FETs with Fmax of 14 GHz per 2 µm gate length were demonstrated in a self-aligned top-gated layout with the highest ever on-state current density of 3 A/mm at Vds = 5 V, field-effect mobility was limited below 200 cm2/Vs. There are only a few reports of a graphene-on-Si platform with on-stage current <0.02 mA/mm. [3]