Dae-Il Kim

Deposition of indium tin oxide films on polycarbonate substrates by direct metal ion beam deposition

Thin indium tin oxide (ITO) films have been deposited onto polycarbonate (PC) substrate without substrate heating by direct metal ion beam deposition (DMIBD) technique and the influence of secondary negative metal ion beam energy on the opto-electrical and surface morphological property of the films have been investigated. For ITO films (100 nm thick) deposited at ion beam energy of 50 eV, the lowest resistivity and the highest optical transmittance was obtained but when using higher ion beam energy (above 75 eV) both conductivity and optical transmittance were decreased. Surface roughness of as deposited ITO thin film at 50 eV is less than that of the bare PC substrate. However, too intense ion beam bombardment on growing film deteriorated the opto-electrical property of ITO films. XPS measurements showed that ITO films grown at 50 eV were fully oxidized and Cs 3d5 peak is also observed. In this study, by using DMIBD technique we were able to obtain ITO films on PC substrate with 5×10−4 Ω cm and above 90% optical transmittance at 550 nm.

Characterization of the Sn Doped In2O3 Film Prepared by DC Magnetron Sputter Type Negative Metal Ion Beam Deposition

Transparent conducting indium tin oxide (ITO) films were prepared on a glass substrate by DC magnetron sputter type negative ion source from a target of a mixture of In2O3 (90%) and SnO2 (10%). In order to investigate the influence of cesium (Cs) partial pressure (PCs) on the optoelectronic property of ITO films, the PCs was varied from 1×10-3 to 2.2×10-3 Pa. The O2/Ar flow rate, working pressure, power density, and substrate temperature were kept constant at 3.6%, 9×10-2 Pa, 2.5 Wcm-2 and 70°C, respectively. By optimizing the PCs at 1.7×10-3 Pa, transparent (transmission ~81% at 550 nm) and conducting (resistivity ~4.3×10-4 Ωcm) ITO films were prepared. Atomic force microscopy (AFM) images showed that the surface morphology also varied significantly with PCs and that the lowest surface rms roughness was 0.6 nm measured at PCs=1.7×10-3 Pa. XPS measurement showed that the Cs concentration in the ITO films was less than 0.2 at%.