Investigating electrical performance and breakdown characteristic of graphene field-effect transistor with different oxides structure.

The graphene field-effect transistor (GFET) with a thin insulating oxide layer can regulate electrical performance under small voltage. After reactive ion etching of 300 nm SiO 2 , the substrates with different shapes and thicknesses are used to fabricate GFET. The electrical performance test proves that GFETs with suspended structures have high carrier mobility. Compared with the suspended structures that should uphold voltage within 15 V, a device with SiO 2 thickness of 10 nm can achieve superior electrical regulation only within 4 V. The thin insulating oxide layer increases the risk of breakdown. Under the high electric field, the thin oxide layer will be broken down to form a conductive channel, and the interface between graphene and substrate will generate metal-semiconductor contact, forming Schottky-like diode. The electrical properties have changed at this stage. There is an electric current flowing through internal conduction, and the transfer characteristics change from bipolar to unipolar. This research provides a new idea to realize small voltage regulation and a basis for judging graphene transistor failure. • Suspended graphene field-effect transistor is fabricated by transferring monolayer graphene to the patterned substrate. • Achieve superior electrical regulation under smaller gate voltage by reducing the thickness of oxide layer. • The carrier mobility of the graphene field-effect transistor with the suspended structure is remarkably improved. • The contact interface forms metal-semiconductor contact and device forms a Schottky-like diode after electrical breakdown. • These results provide a theoretical basis for judging contamination of channel material or device breakdown. [ABSTRACT FROM AUTHOR]