Keywords: magnetic controlled DC sputtering, aluminium doped ZnO, AZO films, zinc oxide, transparent conducting thin films, Scherrer', s Formula, Burstein–Moss shift, carrier mobility, carrier concentration, resistivity, grain size, X–ray diffraction, nanotechnology
The analysis of magnetic controlled DC sputtering AZO films
The Al–doped zinc oxide (AZO) transparent conducting thin films were deposited by the use of magnetic controlled DC sputtering method. To obtain best process parameters, we compare and analyse different process parameters like working pressure and substrate temperature, and properties of AZO films with DC sputtering. The transmittance of AZO film is over 85% at visible region (380∼800 nm). Blue shift effect was observed clearly within 350∼390 nm, as the substrate temperature increases from 225ºC to 325ºC. This is primarily due to the Burstein–Moss shift effect. The FWHM of (002) orientation peak of the XRD decreased with increasing substrate temperature while the grain size, carrier concentration and carrier mobility increased with increasing substrate temperature. The resistivity decreases with the operating temperature due to the combined action of increasing carrier concentration and carrier mobility, and has a minimum resistivity of 0.34 mΩ–cm. The X–ray diffraction peak intensity increases with the increasing substrate temperature. As the substrate temperature increases from 225ºC to 325ºC, the increasing X–ray diffraction peak intensity of (002) is primarily due to the crystallisation of the AZO film. The crystalline size of various AZO films, as can be evaluated by Scherrer's Formula, is around 28-43 nm.