Development of high rate sputtering system for the deposition of transparent conductive thin films with low resistivity and high adhesion on plastic film substrate.

本研究开发了一种高沉积速率的无损伤溅射沉积方法，用于在塑料衬底上沉积低电阻率透明导电薄膜。1)溅射沉积过程中衬底的加热主要是由磁控溅射和面靶溅射中等离子体的电子入射引起的。从靶表面发射的高能二次电子的入射是衬底加热的另一个来源。与磁控溅射系统相比，面对靶溅射系统由于衬底处于无等离子体状态，入射加热能量要小得多。2)为了获得表面光滑度好的薄膜，抑制晶体生长是必要的。在ITO中加入少量Zn可以有效抑制薄膜的结晶生长。抑制晶体生长也能有效地降低薄膜的压应力，在适当的溅射气体压力约为8 m tors时，可以实现无应力薄膜。3)我们发现，在直流模式下，对靶排列相反的双阴极脉冲溅射有助于实现氧化膜的稳定高速率溅射，并且通过保持阳极电位为地电位，可以抑制等离子体中带电粒子对衬底表面的轰击。结果表明，面靶溅射源与磁控管源相结合可以有效地构成双溅射系统。4)我们发现ITO薄膜的电学性能随着衬底位置的变化而发生了显著的变化，并阐明了薄膜的这种不均匀性主要是由于靶表面氧原子和铟原子发射角分布的差异造成的。

In this study, damage-less sputter-deposition method with high deposition rate have been developed for the deposition of transparent conductive thin films with low resistivity on a plastic substrate.1)The substrate heating during sputter-deposition was mainly caused by the incidence of electrons from the plasma in both magnetron sputtering and facing target sputtering. Incidence of high energy secondary electrons emitted from the target surface was one of the other sources for the substrate heating. Compared with the magnetron sputtering system, the amount of the incident heating energy was much lower in facing target sputtering system, since the substrate was kept in a plasma free condition.2)The suppression of crystal growth was necessary to obtain a film with excellent surface smoothness. The addition of small amount of Zn into ITO was effective to suppress the crystal growth of the film. The suppression of crystal growth was also effective to reduce the compressive film stress and stress free films can be realized at a proper sputtering gas pressure around 8 m Torr.3)We showed that pulse sputtering of dual cathodes with opposed target arrangement was useful to realize a stable high rate sputtering of oxide film in a dc mode, and bombardment of substrate surface by charged particles in plasma can be suppressed by keeping the anode potential at earth potential. We also showed that combination of facing targets sputtering source and magnetron source works effectively as a dual sputtering system.4)We found that the electrical properties of the ITO films changes significantly with substrate position, and clarified that this non-uniformity of the film is mainly caused by the differences in the distribution of emission angles between oxygen atoms and In atoms from the target surface.