Room Temperature Processed ZnO Thin Film Transistors Grown by Magnetron Sputtering Using Zirconium Oxide Gate Dielectric

Abstract

A room temperature‐processed ZnO thin film transistors (TFT) with zirconium oxide (ZrO2) are demonstrated as a gate dielectric, fabricated by dc magnetron sputtering. The oxygen flow rate dependence of ZrO2 thin films on the optical, structural, and electrical properties is investigated. Nanocrystalline ZrO2 films with a grain size of 6.2–16.8 nm are obtained at room temperature and grain size is found to be a function of oxygen flow rate during deposition. The electrical characterization of the gate dielectric is carried out using the device structure Al‐ZrO2‐Al. The leakage properties and dielectric constants are computed for the gate dielectric grown at different oxygen flow rates. Further, bottom gate staggered ZnO thin film transistors are fabricated with the configuration glass/Al/ZrO2/ZnO/Al and the devices exhibit a field effect mobility of ≈43 cm2 V−1 s−1, a low operating voltage of 1.5 V and on/off ratio of 103. This work could lead to the possibility of low operating voltage TFTs for the next generation display technologies.

p-channel NiO thin film transistors grown with high k ZrO2 gate oxide for low voltage operation

“…To design a transparent and low voltage operated TFT, the high-k gate oxide materials are most necessary. So far numerous research groups have investigated high-k materials such as TiO 2 , HfO 2 , Ta 2 O 2 , Al 2 O 3 , Y 2 O 3 and ZrO 2 [14][15][16][17][18][19][20]. Among various high-k materials, ZrO 2 has attracted extensively due to its distinctive physical properties such as high dielectric constant (∼27), wide optical band gap, high melting point (∼2700 °C), and thermal stability to attain the favourable device fabrication.…”

“…Moreover, tuning the processing parameters to get excellent capacitance density and low leakage current density is also essential. There are a variety of high-quality oxide semiconductor thin films that can be processed, which includes atomic layer deposition, DC sputtering, RF sputtering, plasma evaporation, Chemical vapour deposition etc, [10,[20][21][22]. Due to consistent film formation, large area coverage, simple methodology, and low cost, DC magnetron sputtering has established as a state of art in the thin film technology and particularly in nanoelectronics.…”