Structural and etching behavior of Al-doped zinc oxide thin film

Transparent aluminum-doped zinc oxide (ZnO: Al or AZO) thin films with high performance were fabricated by reactive mid-frequency (MF) magnetron sputtering from Zn/Al metallic targets (Zn-to-Al mass ratio of 98:2) with a dual magnetron configuration. Then, the influence of deposition parameters on the structure as well as the electrical and optical properties of AZO films were investigated. Moreover, the etching behavior of the deposited films and the structural characteristics of the texture surfaces were analyzed. It is found that (1) the substrate temperature plays a significant role in the growth of the films; (2) films with good crystallinity and tightly-packed columnar structure can be obtained at a proper deposition temperature, the minimum resistivity of which being 4.600 × 10-4 Ω · cm; (3) the moving speed of the substrate obviously affects the film growth, but no significant change in the deposition efficiency is observed; and (4) the film with obvious crystalline texture and columnar structure exhibits a regular rough morphology after being etched in diluted HCl, which favors an effective light trapping to meet the demand of thin-film solar cells.