An ultra clean self-aligned process for high maximum oscillation frequency graphene transistors

Abstract

Owing to its ultra high carrier mobility, graphene transistor shows great application potential as high-frequency electronics. Intrinsic cutoff frequency (fT) of 427GHz has been reported. But the maximum oscillation frequency (fmax) 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 100nm gate-length graphene transistor exhibits a fmax of 105GHz. Our study shows a pathway to fabrication of high-performance graphene transistors for future application in RF circuits.