Cu2O p-type Thin-Film Transistors with Enhanced Switching Characteristics for CMOS Logic Circuit by Controlling Deposition Condition and Annealing in the N2 Atmosphere

Cuprous oxide (Cu 2 O) p-type thin-film transistors (TFTs) can be practically applied for complementary metal oxide semiconductor (CMOS) logic circuits, but the electrical performances are still insufficient due to high off-current and low field-effect mobility. Here, we have demonstrated Cu 2 O TFTs with improved field-effect mobility and low off-current through reduction of cupric oxide (CuO) impurities and dissociative Cu defects with the combination of deposition and annealing conditions. Copper oxide was deposited by radio frequency sputtering in mixed gases of argon and oxygen. After that, the deposited copper oxide was annealed at 800 °C in the tube furnace under a N 2 atmosphere instead of a high vacuum condition. The fabricated Cu 2 O thin film had a high crystalline quality, the ratio of dissociative Cu defects decreased from 11.3 to 3.1%, and the electrical performances of the…