Sputter deposition of Al-doped ZnO films with various incident angles

Al-doped ZnO (AZO) films were sputter deposited on glass substrates heated at 200 degrees C under incident angles of sputtered particles at 0 degrees (incidence normal to substrate), 20 degrees, 40 degrees, 60 degrees, and 80 degrees. In the case of normal incidence, x-ray diffraction pole figures show a strong [001] preferred orientation normal to the film surface. In contrast, in the case wherein the incident angles were higher than 60 degrees, the [001] orientation inclined by 25 degrees-35 degrees toward the direction of sputtered particles. Transmission electron microscopy revealed that the tilt angle of the [001] orientation increased with increasing angle of the incident sputtered particles, whereas the columnar structure did not show any sign of inclination with respect to the substrate plane.