Gigahertz Field-Effect Transistors with CMOS-Compatible Transfer-Free Graphene

Area of Science:

• Materials Science
• Electronics Engineering
• Nanotechnology

Background:

• High-quality graphene on metal-free substrates is crucial for advanced electronic applications.
• Achieving an atomic clean interface and semiconductor-compatible manufacturing is a key challenge.

Purpose of the Study:

• To report a scalable fabrication approach for graphene-based radio frequency field-effect transistors (RF-FETs).
• To demonstrate the potential of these devices for high-speed wireless communications.

Main Methods:

• Graphene growth directly on sapphire substrates using remote-catalyzed chemical vapor deposition (CVD).
• Fabrication of RF-FETs utilizing a mushroom-shaped aluminum oxide (AlOₓ) top gate for self-aligned contacts.

Main Results:

• Demonstrated high extrinsic cutoff frequency (fT) of 10.1 GHz and maximum oscillation frequency (fmax) of 5.6 GHz.
• Achieved enhanced device transconductance and reduced parasitic resistance due to the self-aligned contact design.
• Grown graphene quality is comparable to transferred CVD graphene.

Conclusions:

• The developed remote-catalyzed CVD method provides a scalable route for producing high-quality graphene on sapphire.
• These graphene RF-FETs show significant promise for next-generation high-speed wireless communication systems.