Impact of passivation layer on the subthreshold behavior of p-type CuO accumulation-mode thin-film transistors

In this work, models of p-type CuO metal -oxide- semiconductor (MOS) capacitor and thin-film transistors (TFTs) are established using numerical simulation tools and compared with experimental data, to investigate the impact of a passivation layer on the TFT subthreshold behavior. Simulated transfer curves and hole concentrations of back-gated CuO TFT with 10 mu m channel length confirm the experimental observation of buried-channel and accumulation-mode conduction mechanisms. The subthreshold behavior is analyzed with HfO2 passivation on the top CuO surface varying the densities of fixed oxide charge and interface states, as well as the thickness of the CuO film. The simulation results demonstrate a significant potential improvement of the subthreshold slope and on/off current ratio, mainly thanks to the optimization of the fixed oxide charge densities.