Development of psudobinary amorphous transparent conductive ooxide films and their applications totransparent electrodes

在2004年和2005年的资助研究中，我们利用ZnO或SnO_2靶材和In_2O_3陶瓷靶材在氩气中制备了In_2O_3-ZnO和In_2O_3-SnO_2薄膜。在添加Al_2O_3或Ga_2O_3杂质时，研究了它们的电学和光学性质。将Al_2O_3或Ga_2O_3杂质添加到ZnO靶材中。各靶的放电电流在0 ~ 80 mA范围内变化，δ=I_<Zn>/(I_<Zn>+I_<In>)的电流比与薄膜中Zn和In的含量比基本一致。Ga_2O_3的影响与Al_2O_3相同。δ值为0 ~ 0.2、0.2 ~ 0.6、0.6 ~ 0.8和0.8 ~ 1.0时，分别得到In_2O_3结构、非晶结构、同源结构和ZnO结构。随着Ga_2O_3和Al_2O_3的增加，出现非晶相的δ值在δ=0.23 ~ 0.67之间变化。两种情况下，非晶相的电阻率最低。这些杂质的掺入并没有对非晶相膜产生严重的影响，尽管这些杂质的掺入增加了同源晶体膜的电阻率。这些数据表明，杂质不充当供体。杂质的作用是增大光学带隙，提高蓝色区域的光学透明度。这是随着Ga_2O_3和Al_2O_3的增加而引起的内应力。在两种薄膜中，非晶薄膜的表面都比晶体薄膜光滑。这些结果表明，非晶膜在未来的透明导电氧化膜中具有良好的潜力。

In the research of grant-in-aid for 2004 and 2005, we deposited In_2O_3-ZnO and In_2O_3-SnO_2 films in Ar gas by facing target sputtering system using ZnO or SnO_2 target and In_2O_3 ceramic targets. We investigated their electrical and optical properties under additional Al_2O_3 or Ga_2O_3 impurities. The impurities of Al_2O_3 or Ga_2O_3 were added to ZnO targets. The discharge current of each target was changed from 0 to 80 mA and the current ratio of δ=I_<Zn>/(I_<Zn>+I_<In>) was nearly the same as the content ratio of Zn and In in the film. The influence of Ga_2O_3 wais the same as those of Al_2O_3. At the δ values of 0〜0.2,0.2-0.6,0.6-0.8 and 0.8-1.0, In_2O_3 structure, amorphous structure, homologous and ZnO structure were obtained, respectively. With increasing Ga_2O_3 or Al_2O_3, the δ values, where amorphous phase appeared, shifted to δ=0.23 to 0.67. The lowest resistiviity appeared at the amorphous phase for both cases. The incorporation of these impurities did not induce a severe influence on the amorphous phase film, although the resistiviity of homologous crystalline films increased with incorporation of these impurities. These data show that the impurities does not act as donors. The role of the impurity appeared in the enlargement of optical band gap, which improve the optical transparency at the blue region. This was induced by the internal stress with increasing Ga_2O_3 and Al_2O_3. In both films, the surface of amorphous films were smoother than those of crystalline films. These results suggest that the amorphous films have a excellent potential for future transparent conductive oxide films.