p‑Channel Oxide Thin Film Transistors Using\nSolution-Processed Copper Oxide

Abstract

Cu₂O thin films were synthesized\non Si (100) substrate with thermally grown 200-nm SiO₂ by\nsol–gel spin coating method and postannealing under different\noxygen partial pressure (0.04, 0.2, and 0.9 Torr). The morphology\nof Cu₂O thin films was improved through N₂ postannealing\nbefore O₂ annealing. Under relatively high oxygen partial\npressure of 0.9 Torr, the roughness of synthesized films was increased\nwith the formation of CuO phase. Bottom-gated copper oxide (Cu_<i>x</i>O) thin film transistors (TFTs) were fabricated\nvia conventional photolithography, and the electrical properties of\nthe fabricated TFTs were measured. The resulting Cu₂O TFTs\nexhibited <i>p</i>-channel operation, and field effect mobility\nof 0.16 cm²/(V s) and on-to-off drain current ratio of\n∼1 × 10² were observed in the TFT device annealed\nat <i>P</i>_O₂ of 0.04 Torr. This study\npresented the potential of the solution-based process of the Cu₂O TFT with p-channel characteristics for the first time.