In this paper we present bottom-gate-type ZnO-based TFTs with low threshold voltages fabricated with a conventional SiO$_2$ gate insulator by radio-frequency (RF) magnetron sputtering at room temperature. The SiO$_2$ is used as a gate insulator, and i...
In this paper we present bottom-gate-type ZnO-based TFTs with low threshold voltages fabricated with a conventional SiO$_2$ gate insulator by radio-frequency (RF) magnetron sputtering at room temperature. The SiO$_2$ is used as a gate insulator, and it is possible to achieve a low gate leakage current ($<$10 pA) by using this conventional SiO$_2$ oxide without new gate oxide materials.
The ZnO film also has good uniformity and transparency. The ZnO TFTs operate in the enhancement mode with a threshold voltage of 2.5 V. A mobility of 0.018 cm$^2$/(V$\cdot$s), an on/off ratio of about 10$^4$, and a gate voltage swing of 1.7 V/decade are obtained. We successfully demonstrate that a ZnO TFT with comparable electrical characteristics can be fabricated by utilizing the conventional SiO$_2$ gate insulator. It is also possible to reduce the power consumption due to their low threshold voltage and low leakage current.