Improved Subthreshold Swing and Gate-Bias Stressing Stability of p-Type $\hbox{Cu}_{2}\hbox{O}$ Thin-Film Transistors Using a $\hbox{HfO}_{2}$ High- $k$ Gate Dielectric Grown on a $\hbox{SiO}_{2}/\hbox{Si}$ Substrate by Pulsed Laser Ablation

p-Type Cu
₂
O thin films and HfO
₂
high-
k
gate dielectrics are deposited by pulsed laser ablation. p-Type Cu
₂
O metal-oxide-semiconductor capacitors and thin-film transistors (TFTs) are then fabricated and investigated. Experimental results show that a HfO
₂
/SiO
₂
-stacked gate dielectric can effectively improve interface properties and decrease gate-leakage current when compared with a SiO
₂
gate dielectric. Thus, increased mobility, a decreased subthreshold swing, and enhanced gate-bias-voltage stressing stability have been achieved for the relevant Cu
₂
O TFTs. Bottom-gate and top-source/drain-contact p-channel Cu
₂
O TFTs (
W
/
L
= 500/20 μm) with the HfO
₂
/SiO
₂
-stacked gate dielectric exhibit superior performance with a saturation-carrier-mobility value of 2.7 cm
²
/V·s, an on-off current ratio of 1.5×10
⁶
, 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.