Some special phenomena observed from in-line sputtered aluminum doped zinc oxide films

Abstract

In-line sputtered aluminum doped zinc oxide (AZO) films with different substrate temperature have been made. Anisotropic stress of AZO films produced during in-line sputtering was proposed before. This work reports more special phenomena observed from in-line sputtered AZO films attributed to anisotropic stress effect. Three different types of AZO films' surface morphology: a. rounded grain and nearly uniform grain size, b. rounded grain and apparently non-uniform grain size and c. polygonal grain processed with increasing substrate temperature were observed. Usual reported morphology change of AZO films with increasing substrate temperature is rounded grain and uniform grain size growth. Asymmetry judgment of X-ray diffraction zinc oxide (002) peak shape was proposed by checking right part divided by left part of full width at half maximum. Asymmetry of measured X-ray diffraction peak shape was found corresponding to zinc oxide (002) crystal plane. Special AZO films' phenomena of surface morphology and the asymmetry of measured X-ray diffraction peak shape give more hints on anisotropic stress during in-line sputtering process. This work contributes to industries like thin films solar cells, touch panel, light emitting diodes if AZO films were considered to be used as transparent electrodes.