Deep-submicron Graphene Field-Effect Transistors with State-of-Art f.

In order to conquer the short-channel effects that limit conventional ultra-scale semiconductor devices, two-dimensional materials, as an option of ultimate thin channels, receive wide attention. Graphene, in particular, bears great expectations because of its supreme carrier mobility and saturation velocity. However, its main disadvantage, the lack of bandgap, has not been satisfactorily solved. As a result, maximum oscillation frequency (f) which indicates transistors' power amplification ability has been disappointing. Here, we present submicron field-effect transistors with specially designed low-resistance gate and excellent source/drain contact, and therefore significantly improved f. The fabrication was assisted by the advanced 8-inch CMOS back-end-of-line technology. A 200-nm-gate-length GFET achieves f/f = 35.4/50 GHz. All GFET samples with gate lengths ranging from 200 nm to 400 nm possess f 31-41% higher than f, closely resembling Si n-channel MOSFETs at comparable technology nodes. These results re-strengthen the promise of graphene field-effect transistors in next generation semiconductor electronics.