Numerical Investigation for Scale-Up of an Electron Cyclotron Resonance Plasma for Fluorine-Doped Tin Oxide Thin Film Production.

Abstract

A low-temperature process is required to deposit fluorine doped tin oxide (FTO) as a transparent conductive oxide on polyethylene terephthalate (PET) substrate, as the latter is polymeric and has a low melting point. An electron cyclotron resonance (ECR) plasma system is the best way to deposit metal oxide with high transparency and electrical conductivity at temperatures below 100 °C. Characteristics of an ECR plasma include its high ionization energy and electron density; however, its use is limited in large-scale deposition. In order to overcome this limitation, a large-scale ECR plasma system with a dual microwave generator was designed by numerical investigation of a laboratory-scale ECR plasma system. FTO films prepared in the laboratory-scale and large-scale systems were compared. The change in electrical resistivity and optical transmittance with deposition pressure in the large-scale ECR plasma system with dual linear microwave generator is similar to that observed in the laboratory-scale ECR plasma system. The velocity distribution of active species near the substrate in the large-scale ECR plasma system showed a very similar pattern to that in the laboratory-scale ECR plasma system over a range of 1.5×10-2 to 0.8×10-2 m/s. The electrical resistivity and optical transmittance of FTO films deposited by a large-scale ECR plasma system using a dual microwave generator had respective values of 4.3×10-3 ~ 9.18×10-3 Ω ·cm and 86.5~88.2%.