Oblique Angle Sputtering of ZnO:Ga Thin Films

RF diode sputtering of ZnO:Ga thin films by three types of deposition at constant oblique-angle (80°) configuration is presented: simple oblique deposition, oblique depositions by substrate sequential turning around the substrate normal - double by an 180° angle and four-times by 90°. XRD patterns and azimuthal line profiles confirmed their inclined (002) texture and SEM/TEM cross-section analyses indicated the columnar crystallic structures: tilted by about 11°, 2D- and 3D- “pseudo-zigzag” ones. Both inclined texture and tilted columnar structure of the films increased their optical transmittance and widened their direct optical band-gap.