Improved Subthreshold Swing and Gate-Bias Stressing Stability of p-Type Cu₂O Thin-Film Transistors Using a HfO₂ High-k Gate Dielectric Grown on a SiO₂/Si Substrate by Pulsed Laser Ablation

p-Type Cu2O thin films and HfO2high-kgate dielectrics are deposited by pulsed laser ablation. p-Type Cu2O metal-oxide-semiconductor capacitors and thin-film transistors (TFTs) are then fabricated and investigated. Experimental results show that a HfO2/SiO2-stacked gate dielectric can effectively improve interface properties and decrease gate-leakage current when compared with a SiO2gate dielectric. Thus, increased mobility, a decreased subthreshold swing, and enhanced gate-bias-voltage stressing stability have been achieved for the relevant Cu2O TFTs. Bottom-gate and top-source/drain-contact p-channel Cu2O TFTs (W/L= 500/20 μm) with the HfO2/SiO2-stacked gate dielectric exhibit superior performance with a saturation-carrier-mobility value of 2.7 cm2/V·s, an on-off current ratio of 1.5×106, a subthreshold swing of 137 mV/dec, and a threshold-voltage shift of 1.4 V after gate-bias stress at 10 V for 3600 s.