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Complementary Schottky diode formation with carbon buffer and p-doped single layer graphene on intrinsic SiC via fluorine intercalation

Lee, Sang Yeon, Kim, Jinseo, Ahn, Seungbae, Jeon, Ki-Joon, Seo, Hyungtak
Carbon 2019 v.142 pp. 254-260
diodes, electrical properties, electronic circuits, fluorine, gases, graphene, silicon carbide, transistors
A practical application of graphene is in transistors and diodes fabricated through processes compatible with integrated circuit fabrication processes that are currently used. In this paper, a highly controlled gas phase fluorination treatment (using XeF2) of an intrinsic Si-terminated SiC (i-SiC) substrate and a (6√3ⅹ6√3)R30° carbon buffer layer is shown to effectively convert the buffer layer to p-doped SLG (p-SLG), which is decoupled from the i-SiC substrate through F intercalation. The electrical properties of two diode structures, (1) metal/SiC with buffer layer and (2) p-SLG/SiC, were investigated considering the bias-dependent carrier injection at each interface. The analysis results suggest that the diode turn-on for each diode is due to carrier injection from the metal or p-SLG to the i-SiC substrate, with an exponential modulation of the thermionic injection driven by the image barrier lowering effect. A complementary SLG-based SiC diode formation scheme is demonstrated, as hole injection from p-SLG is the origin of positive bias diode turn-on in the second diode type, whereas the diode having metal/SiC with buffer structure showed negative bias turn-on.