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This paper investigated the temperature effects on the RF performances of the epitaxial bilayer graphene field-effect transistors (EBG-FETs) on a SiC substrate over a temperature range of 25–200 °C under the atmospheric environment. The temperature dependence of the cutoff frequency fT and the maximum oscillation frequency fmax of the EBG-FETs with an identical gate-length and different gate-widths were measured by small-signal measurement up to 40 GHz. The results show that EBG-FETs are capable of operating at high temperature up to 200 °C with workable amounts of thermally induced performance degradation. To gain further insight into the underlying physics of the device parameters affected by temperature, the small signal device parameter variations with ambient temperature are discussed. This work reveals the great potential of graphene in high temperature device applications.

Owing to its ultra high carrier mobility, graphene transistor shows great application potential as high-frequency electronics. Intrinsic cutoff frequency ( f T ) of 427 GHz has been reported. But the maximum oscillation frequency ( f max ) remains low, limiting its use in practical radio-frequency (RF) circuits. Here, we report an ultra clean self-aligned graphene transistors fabrication by pre-deposition of gold film on graphene as protection layer. This improved self-aligned fabrication keeps graphene away from any possible contamination, which makes our graphene transistors show good gate coupling and less parasitics, thus good dc and RF performances. The 100 nm gate-length graphene transistor exhibits a f max of 105 GHz. Our study shows a pathway to fabrication of high-performance graphene transistors for future application in RF circuits.