Oriented Tin-Doped Indium Oxide Films on <001> Preferred Oriented Polycrystalline ZnO Films

<111>-oriented tin-doped indium oxide (ITO) films were deposited by rf magnetron sputtering on ZnO-coated glass substrates (ZnO/glass). The ZnO underlayers were also deposited by rf magnetron sputtering and have been known to exhibit <001> preferred orientation in a wide range of deposition conditions. The X-ray diffraction profiles of the ITO films deposited on the ZnO/glass showed predominant <111> orientation without any differently oriented crystallites, whereas the ITO films deposited on bare glass substrates (ITO/glass) under the same deposition conditions showed <100>-preferred orientation with small areas of several other orientations. A mechanism of the heteroepitaxial growth of In 2 O 3 (111)|| ZnO(001) was explained by comparing the atomic configurations of oxygen between the oxygen mostly dense-packed planes of In 2 O 3 and ZnO parallel to In 2 O 3 (111) and ZnO(001) planes, respectively. Sn concentrations and lattice constants of the <111>-oriented films (ITO/ZnO/glass) were found to be greater than those of <100> preferred oriented films (ITO/glass) in spite of the fact that the target and deposition conditions were the same, which could be associated with the electrical properties of the films.