Influence of the film thickness on the structure, optical and electrical properties of ITO coatings deposited by sputtering at room temperature on glass and plastic substrates

Abstract

Transparent and conductive indium tin oxide (ITO) films with thickness between 0.2 and 0.7 µm were deposited by sputtering at room temperature on glass and polyethylene terephthalate (PET) substrates. All films were polycrystalline, with crystallite size increasing and lattice distortion decreasing when the film thickness was increased. Besides, transmission in the near-infrared region is found to be decreasing and carrier concentration increasing when the film thickness was increased. For the same thickness, the lattice distortion is slightly lower and the carrier concentration higher for the layers grown on PET substrates. A direct relationship between the lattice distortion and the free carrier concentration has been established, applying to the films grown on glass and plastic substrates. By adjusting ITO coating thickness, sheet resistance below 15 sq −1 and average visible transmittance about 90% have been achieved by sputtering at room temperature.

Structural and morphological properties of ITO thin films grown by magnetron sputtering

“…Various techniques, such as electron beam evaporation [7], ion beam-assisted deposition [8], pulsed laser ablation [9,10], ion implantation [11] and RF/DC magnetron sputtering [12][13][14], are applied for deposition of ITO thin films. Besides the process parameters, the thickness also can affect the properties of the samples [15][16][17][18][19][20][21][22].…”

Low temperature remote plasma sputtering of indium tin oxide for flexible display applications

“…For growth onto flexible substrates however, this is not feasible due to the temperature sensitive nature of the organic material. Hence the deposition of good quality ITO onto polymeric materials without heating the substrates either during or post deposition still represents a significant challenge [10,[12][13][14].…”

A new architecture as transparent electrodes for solar and IR applications based on photonic structures via soft lithography

“…(Figure 3(b)) Therefore, an optimal thickness of ITO needs to be chosen as compromise between the best optical and electrical properties. the sheet resistance and electrical resistivity of ITO on SLG and polyethylene terephthalate (PET) polymer films at different thickness [8] Furthermore, ITO is very brittle [7] and has poor mechanical stability, in addition to indium's high cost as a limited resource. Figure 4 shows a 100nm thick ITO under different tensile loading along the horizontal direction.…”

“…[7] There are trade-off between the optical and electrical properties of ITO depending the film thickness. [8] These disadvantages have motivated the search for alternative conducting electrodes with similar or better performance. In recent research efforts, carbon nanotube networks, graphene films, silver nanowire meshes and nanopatterned metal grids have been evaluated as potential replacements for ITO based electrodes.…”