Effect of front and back gates on β-Ga2O3 nano-belt field-effect transistors

• Published in: Applied physics letters 2016-08, Vol.109 (6)
• Main Authors: Ahn, Shihyun, Ren, Fan, Kim, Janghyuk, Oh, Sooyeoun, Kim, Jihyun, Mastro, Michael A., Pearton, S. J.
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Applied physics; Current density; Electric potential; Exfoliation; Field effect transistors; Gallium oxides; Morphology; Nanoelectronics; Semiconductor devices; Silicon dioxide; Silicon substrates; Transconductance; Transistors
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4960651

Field effect transistors (FETs) using SiO2 and Al2O3 as the gate oxides for the back and front sides, respectively, were fabricated on exfoliated two-dimensional (2D) β-Ga2O3 nano-belts transferred to a SiO2/Si substrate. The mechanical exfoliation and transfer process produced nano-belts with smooth surface morphologies and a uniform low defect density interface with the SiO2/Si substrate. The depletion mode nanobelt transistors exhibited better channel modulation with both front and back gates operational compared to either front or back-gating alone. The maximum transconductance was ∼4.4 mS mm−1 with front and back-gating and ∼3.7 mS mm−1 with front-gating only and a maximum drain source current density of 60 mA mm−1 was achieved at a drain-source voltage of 10 V. The FETs had on/off ratios of ∼105 at 25 °C with gate-source current densities of ∼2 × 10−3 mA mm−1 at a gate voltage of −30 V. The device characteristics were stable over more than a month for storage in air ambient and the results show the potential of 2D β-Ga2O3 for power nanoelectronics.