Graphene field effect transistor (GFET) has attracted significant attention for potential radio-frequency (RF) applications due to its outstanding carrier mobility and high carrier saturation velocity. Intrinsic cutoff frequency (fT ) of 427 GHz has been reported [1] and is starting to approach the values of the best of Si-based transistors. But the maximum oscillation frequency (fmax) remains low, limiting its use in practical RF circuits. The reported fmax values are usually less than 50 GHz, and very recently one 70 GHz GFET was reported. [2] f max is a far more relevant parameter for most circuits, since it accounts for device parasitics and defines the frequency up to which the transistor provides power gain. The very low fmax has become the bottleneck for the application of GFETs in practical circuits. 

Here, we report an improved self-aligned GFET fabrication process and the as prepared devices show good gate coupling and less parasitics, thus good dc and RF performances. The 100 nm gate-length graphene transistor exhibits a record fmax of 105 GHz. Our study shows a pathway to fabrication of high-performance graphene transistors for future application in RF circuits.

Graphene field effect transistor (GFET) has attracted significant attention for potential radio-frequency (RF) applications due to its outstanding carrier mobility and high carrier saturation velocity. Intrinsic cutoff frequency (fT ) of 427 GHz has been reported [1] and is starting to approach the values of the best of Si-based transistors. But the maximum oscillation frequency (fmax) remains low, limiting its use in practical RF circuits. The reported fmax values are usually less than 50 GHz, and very recently one 70 GHz GFET was reported. [2] f max is a far more relevant parameter for most circuits, since it accounts for device parasitics and defines the frequency up to which the transistor provides power gain. The very low fmax has become the bottleneck for the application of GFETs in practical circuits. 

Here, we report an improved self-aligned GFET fabrication process and the as prepared devices show good gate coupling and less parasitics, thus good dc and RF performances. The 100 nm gate-length graphene transistor exhibits a record fmax of 105 GHz. Our study shows a pathway to fabrication of high-performance graphene transistors for future application in RF circuits.