Room temperature deposition of very thin and flexible crystalline ITO thin film using 3-D facing-magnetron sputtering plasma source

The lowest resistivity of ~4.8 × 10⁻⁴ Ωcm and an average visible transmittance of 82% in very thin ITO films of thickness ≤35 nm were produced by the technique 3-D confined magnetron sputtering (3DCMS) at room temperature. Utilizing two DC power supplies to the side and top targets and controlling the plasma parameters, we fabricated crystalline microstructures up to ~24 nm and 52 nm by incorporating a high collisional environment in high-density plasmas. Material properties are carefully studied in light of the formation of crystalline microstructure. The measured grain sizes are reasonably matched with the theoretical estimation using the two-body collision model, taking into account the formation of tens of nanometers-sized grains or nanoclusters by add-atoms/coagulation. Also, the chemical properties of the films were carefully analyzed. The fabricate ITO thin films have shown good bending capabilities with a bending radius of 3 mm and the cycle of 30,000 for their potential flexible applications.