Schottky Barrier Height engineering and electrical performance enhancement using ZnO as an interlayer in MIS contact structures for SnO thin-film transistors

초록

Oxide semiconductor materials are promising channel candidates for nanoscale electronic devices in threedimensional integration structures, due to reliable performance and fabrication under low-temperature processes. Among these, SnO is a promising material due to the remarkably high hole mobility compared to other ptype oxide semiconductor materials. However, the potential of SnO is limited due to the high contact resistivity which degrades the electrical performance of SnO thin-film transistors (TFTs). In this study, the metal-interlayersemiconductor (MIS) structure is proposed utilizing ZnO as a thin insulator layer (IL) to reduce the hole Schottky Barrier Height (SBH) and contact resistivity at the source/drain contact of SnO. The MIS structure enabled Fermi- level (FL) unpinning and introduced interfacial dipole, aligning the effective work function of Pt close to VBM of SnO and thereby reducing the SBH. Adopting the MIS structure resulted in significant performance enhancements: contact resistivity was reduced from 7.30 x 10-2 to 2.2 x 10-4 ohm center dot cm2, reaching one of the best values reported; SBH reduced from 0.53 to 0.38 eV; Therefore, the proposed MIS structure in SnO showed crucial effect for overcoming the primary limitation that degraded the electrical characteristics of SnO, ultimately leading to a significant enhancement in the performance of p-type oxide semiconductor based electronic devices.

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