ZTO/n-Si thin film is produced to investigate tunneling phenomena by interface characteristics by the depletion layer. For diversity of the depletion layer, the thin film of ZTO is heat treated after deposition, and the gpolarization is found to change depending on the heat treatment temperature and capacitance. The higher the heat treatment temperature is, the higher the capacitance is, because more charges are formed, the highest at 150 °C. The capacitance decreases at 200 °C. ZTO heat treated at 150 °C shows tunneling phenomena, with low non-resistance and reduced charge concentration. When the carrier concentration is low and the resistance is low, the depletion layer has an increased potential barrier, which results in a tunneling phenomenon, which results in an increase in current. However, the ZTO thin film with high charge or high resistance shows a Schottky junction feature. The reason for the great capacitance increase is the increased current due to tunneling in the depletion layer.

The transfer characteristics of zinc tin oxide(ZTO) on silicon dioxide(SiO2) thin film transistor generally depend on the electrical properties of gate insulators. SiO2 thin films are prepared with argon gas flow rates of 25 sccm and 30 sccm. The rate of ionization of SiO2(25 sccm) decreases more than that of SiO2(30 sccm), and then the generation of electrons decreases and the conductivity of SiO2(25 sccm) is low. Relatively, the conductivity of SiO2(30 sccm) increases because of the high rate of ionization of argon gases. Therefore, the insulating performance of SiO2(25 sccm) is superior to that of SiO2(30 sccm) because of the high potential barrier of SiO2(25 sccm). The ZTO/SiO2 transistors are prepared to research the CO2 gas sensitivity. The stability of the transistor of ZTO/SiO2(25 sccm) as a high insulator is superior owing to the high potential barrier. It is confirmed that the electrical properties of the insulator in transistor devices is an important factor to detect gases.

We have investigated the properties of thin film transistors(TFT) fabricated using zinc tin oxide(ZTO) thin films deposited via on-axis sputtering and FTS methods. ZTO thin films deposited by FTS showed lower root-mean-square(RMS) roughness and more uniformity than those deposited via on-axis sputtering. We observed enhanced electrical properties of ZTO TFT deposited via FTS. The ZTO films were deposited at room temperature via on-axis sputtering and FTS. The as-deposited ZTO films were annealed at 400 oC. The TFT using the ZTO films deposited via FTS process exhibited a high mobility of 12.91 cm2/V.s, a low swing of 0.80 V/decade, Vth of 5.78 V, and a high Ion/off ratio of 2.52 × 106.

To study the characteristics of ZTO, which is made using a target mixed ZnO:SnO2= 1:1, the ZnO and SnO2 were analyzed using PL, XRD patterns, and electrical properties. Resulting characteristics were compared with the electrical characteristics of ZnO, SnO2, and ZTO. The electrical characteristics of ZTO were found to improve with increasing of the annealing temperature due to the high degree of crystal structures at high temperature. The crystal structure of SnO2 was also found to increase with increasing temperatures. So, the structure of ZTO was found to be affected by the annealing temperature and the molecules of SnO2; the optical property of ZTO was similar to that of ZnO. Among the ZTO films, ZTO annealed at the highest temperature showed the highest capacitance and Schottky contact.