Effects of co-sputtering powers on the properties of silicon-incorporated zinc oxide used as a channel layer of thin film transistors

• The co-sputtering method was used to prepare Si-incorporated ZnO (SZO) films.
• Characteristics of SZO films were examined according to the Si sputtering power.
• Characteristics of the SZO film were related to the changes of Vo and SiOx bonds.
• Excessive Si resulted in an increase in the SiOx bonds instead of the SiO2 bonds.

The co-sputtering method was used to prepare Si-incorporated ZnO (SZO) films. The changes in the electrical resistivity, crystalline structure, optical transmittance, and chemical bonding of SZO films were examined according to the sputtering power applied to the Si target. The resistivity of the SZO film strongly depended on the sputtering power of the Si target and varied in a wide range of approximately 10− 3–107 Ω cm. With an increase in the Si sputtering power, the crystalline structure of SZO films changed from polycrystalline to amorphous. The average transmittance of all the SZO films within the wavelength-range of 400–700 nm was at least 80%. X-ray photoelectron spectroscopy measurement showed that the changes in the resistivity and optical band gap of the SZO film according to the Si sputtering power were closely related to the changes in the oxygen vacancies and SiOx bonds in the film. Finally, the bottom-gate-type SZO-TFTs were fabricated and their transistor actions were presented.