Zinc tin oxide transparent thin film transistors (ZTO TTFTs) were fabricated by using n`` Si wafers as gate electrodes. Indium (In), aluminum (Al), indium tin oxide (ITO), silver (Ag), and gold (Au) were employed for source and drain electrodes, and the mobility and the threshold voltage of ZTO TTFTs were observed as a function of electrode. The ZTO TTFTs adopting In as electrodes showed the highest mobility and the lowest threshold voltage. It was shown that Ag and Au are not suitable for the electrodes of ZTO TTFTs. As the results of this study, it is considered that the interface properties of electrode/ZTO are more influential in the properties of ZTO TTFTs than the conductivity of electrode.

Zinc tin oxide transparent thin film transistors (ZTO TTFTs) were fabricated on oxidized n+ Si wafers. The thickness of 30 nm Al2O3 films were deposited on the oxidized Si wafers by atomic layer deposition, which acted as the gate insulators of ZTO TTFTs. The Al2O3 films were rapid-annealed at 400 , 600 , 800 , and 1,000 , respectively. Active layers of ZTO films were deposited on the Al2O3/SiO2 coated n+ Si wafers by rf magnetron sputtering. Mobility and threshold voltage were measured as a function of the rapid-annealing temperature. X-ray photoelectron spectroscopy (XPS) were carried out to observe the chemical bindings of Al2O3 films. The annealing effects of gate-insulator on the properties of TTFTs were analyzed based on the results of XPS.

Transparent thin film transistors were fabricated on n+-Si wafers coated by Al2O3/SiO2. Zinctin oxide (ZTO) films deposited by rf magnetron sputtering were employed for active layers. The mobility(μs), threshold voltage (VT), and sub threshold swing (SS) dependances on ZTO thickness were analyzed. The VT decreased with increasing ZTO thickness. The μs raised from 5.1 cm2/Vsec to 27.0 cm2/Vsec byincreasing ZTO thickness from 7 nm to 12 nm, and then decreased with ZTO thickness above 12 nm. The SS was proportional to ZTO thickness.

Bottom-gate tin oxide (SnO2) thin film transistors (TFTs) were fabricated on N+ Si wafersused as gate electrodes. 60-nm-thick SnO2 thin films acting as active layers were sputtered onSiO2/Al2O3 films. The SiO2/Al2O3 films deposited on the Si wafers were employed for gate dielectrics. Inorder to increase the resistivity of the SnO2 thin films, oxygen mixed with argon was introduced into thechamber during the sputtering. The mobility of SnO2 TFTs was measured as a function of the flow ratioof oxygen to argon (O2/Ar). The mobility variation with O2/Ar was analyzed through studies oncrystallinity, oxygen binding state, optical properties. X-ray diffraction (XRD) and XPS (X-rayphotoelectron spectroscopy) were carried out to observe the crystallinity and oxygen binding state ofSnO2 films. The mobility decreased with increasing O2/Ar. It was found that the decrease of the mobilityis mainly due to the decrease in the polarizability of SnO2 films.

Mg doped zinc tin oxide (ZTOMg) thin films were prepared on glasses by rf magnetron sputtering. O was introduced into the chamber during the sputtering. The optical properties of the films as a function of oxygen flow rate were studied. The crystal structure, elementary properties, and depth profiles of the films were investigated by X-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and secondary ion mass spectrometry (SIMS), respectively. Bottom-gate trdnsparent thin film transistors were fabricated on N Si wafers, and the variation of mobility, threshold voltage etc. with the oxygen flow rate were observed.

Transparent thin film transistors (TTFT) were fabricated on N+ Si wafers. SiO2, Si3N4/SiO2 and Al2O3/SiO2 grown on the wafers were used as gate insulators. The rf magnetron sputtered zinc tin oxide (ZTO) films were adopted as active layers. N+Si wafers were wet-oxidized to grow SiO2. Si3N4 and Al2O3 films were deposited on the SiO2 by plasma enhanced chemical vapor deposition (PECVD) and atomic layer deposition (ALD), respectively. The mobility, Ion/Ioff and subthreshold swing (SS) were obtained from the transfer characteristics of TTFTs. The properties of gate insulators were analyzed by comparing the characteristics of TTFTs. The property variation of the ZTO TTFTs with time were observed.

Transparent thin film transistors (TTFT) were fabricated using the rf magnetron sputtered ZnO-SnO2 films as active layers. A ceramic target whose Zn atomic ratio to Sn is 2:1 was employed for the deposition of ZnO-SnO2 films. To study the post-annealing effects on the properties of TTFT, ZnO-SnO2 films were annealed at 200℃ or 400℃ for 5 min before In deposition for source and drain electrodes. Oxygen was added into chamber during sputtering to raise the resistivity of ZnO-SnO2 films. The effects of oxygen addition on the properties of TTFT were also investigated. 100 nm Si3N4 film grown on 100 nm SiO2 film was used as gate dielectrics. The mobility, Ion/Ioff, interface state density etc. were obtained from the transfer characteristics of ZnO-SnO2 TTFTs.