Synthesis of transparent conductive films with very low resistivity

用臭氧或氢的溅射方法合成了具有代表性的薄膜透明导电氧化物，如ITO或GZO，具有极低的电阻率。利用合金靶的反应磁控溅射沉积透明导电氧化物(TCO)有望以较高的沉积速率实现低成本沉积。然而，在较低的衬底温度下，与使用氧化物陶瓷靶材溅射相比，很难沉积结晶度较高的完全氧化膜。本研究采用氧气-臭氧混合气体作为反应气体，在反应磁控溅射过程中强化薄膜生长过程中的氧化。采用直流反应溅射法制备了掺锡氧化铟薄膜，采用In-Sn10wt%合金靶材，在未加热且沉积温度低于60℃的钠钙玻璃衬底上引入氧气-臭氧混合气体(臭氧体积分数：0~10vol.%)。在沉积过程中观察到了引入臭氧对靶面和薄膜表面的氧化增强作用。在靶表面未被充分氧化的“金属模区”，通过引入臭氧成功地沉积了多晶透明的ITO薄膜，因此沉积速率比在“氧化物模区”的沉积速率高一个数量级。在使用ITO氧化物靶的溅射沉积的情况下，氢的引入被证实有效地降低了薄膜的电阻率。

Synthesis of representative thin film transparent conductive oxides such as ITO or GZO with very low resistivity have been studied using sputtering processes with ozone or hydrogen introduction. Reactive magnetron sputtering using alloy targets to deposit transparent conductive oxide (TCO) is expected to have a high potential for low cost deposition with high deposition rates. However, at low substrate temperature fully oxidized films with high crystallinity are rather difficult to deposit compared with the sputtering using oxide ceramic targets. In this study oxygen-ozone mixture gas was used as a reactive gas for the enhancement of the oxidation during film growth in the reactive magnetron sputtering processes. Tin-doped Indium Oxide (ITO) films were deposited by dc reactive sputtering using an In-Sn (Sn:10wt%) alloy target with the introduction of oxygen-ozone mixture gases (ozone: 0〜10 vol.%) on soda-lime glass substrates which were not heated and confirmed to be lower than 60℃ during the deposition. The oxidation enhancement by the ozone introduction was observed for both target surface and film surface during the deposition. Polycrystalline transparent ITO films were successfully deposited by the ozone introduction at the "metal mode" region where the target surface was not fully oxidized and hence deposition rate was higher by about one order of magnitude than the one at "oxide mode". In the case of sputter deposition using an ITO oxide target, hydrogen introduction was confirmed to be effective for decreasing resistivity of the films.