Influence of Oxygen on the Resistivity of Co-Sputtered Transparent AZO Films

In the present work co-sputtering from ceramic and metallic targets is used to reduce the oxygen content in aluminium doped zinc oxide. Films with thickness between 200 and 220nm are sputtered at 100 and 250 degrees C and investigated by X-ray diffraction, energy dispersive spectroscopy, and Hall measurements. It is found that reducing of the incorporated oxygen in the film leads to higher carrier concentration, mainly due to better effective activation of Al donors. Higher temperatures result in better carrier mobility due to improving the crystallinity. The best resistivity of 1.4 x 10(-3) cm of the highly transparent film prepared at 100 degrees C is achieved. A larger oxygen reduction leads to lower resistivity, but also results in the significant deterioration of transmittances.