ITO Films Deposited by Thermionic-enhanced DC Magnetron Sputtering on Unheated Polyethylene Terephthalate Polymer Substrate

摘要

A hot filament system is coupled to DC magnetron sputtering system to provide thermionic emission which contributes to the intensified glow discharge. It is expected to obtain higher crystallinity of indium tin oxide (ITO) thin films grown onto polyethylene terephthalate (PET) substrate at low deposition temperature, Microstructures, electrical and optical properties as a function of film thickness were investigated without and with thermionic emission. Experimental results show that the films deposited with thermionic electron emission enhancement present a higher crystallinity in contrast to an amorphous feature of the deposited films without thermionic electron emission enhancement. ITO dun films deposited on PET by utilizing thermionic electron emission enhancement exhibit an average visible transmittance of 80% and an electrical resistivity of 4.5 × 10 -4 Ω·cm, while it presents a 74% visible transmittance and an electrical resistivity of 1.7 × 10 -3Ω·cm without the use of thermionic enhancement. The increased optical transmittance is ascribed to the reduced lattice scattering and the increased electrical conductivity is ascribed to the increased carrier mobility. Both result from the improved crystalline quality of the deposited ITO films by using thermionic emission.