Synthesis of low resistivity ITO films by a low-pressure plasma sputtering

A novel hot-cathode plasma sputtering technique has been established, enabling the synthesis of ITO films at low pressure while allowing for independent control of various parameters. Furthermore, the electrical characteristics of the films can be assessed in a vacuum using the Van der Pauw method. Utilizing this equipment, we explored the electrical characteristics of ITO films deposited on glass substrates from an ITO target (In₂O₃ containing 5wt% SnO₂). We analyzed how different deposition parameters influence the electrical properties of the films, and concluded that the low target voltage is important as one of influencing factors which improves the resistivity of films under certain excitation conditions of the plasma. The ITO films of low resistivity of 1.9×10⁻⁴Ωcm are synthesized at the target voltage of -200V when the working Ar pressure is 1×10⁻³Torr for the plasma excitation.