Electrical and optical properties of ZnO thin film as a function of deposition parameters

Al-doped zinc oxide (AZO) and undoped zinc oxide (ZO) films have been prepared by rf magnetron sputtering. Films with low resistivities were achieved by using an Al-doped ZnO target and films with higher resistivities can be obtained by introducing oxygen during deposition. An AZO thin film which was fabricated with an rf power of 180 W, a sputtering pressure of 10 mTorr and thickness of 5000 Å showed the lowest resistivity of 1.4×10⁻⁴ Ω cm and transmittance of 95% in the visible range, and ZO film made by reactive sputtering with the above 10% oxygen content had the highest resistivity of 6×10¹⁴ Ω cm.