Crystallinity, etchability, electrical and mechanical properties of Ga doped amorphous indium tin oxide thin films deposited by direct current magnetron sputtering

Indium tin oxide (ITO) and Ga-doped ITO (ITO:Ga) films were deposited on glass and polyimide (PI) substrates by direct current (DC) magnetron sputtering using different ITO:Ga targets (doped-Ga: 0, 0.1 and 2.9 wt.%). The films were deposited with a thickness of 50 nm and then post-annealed at various temperatures (room temperature-250 °C) in a vacuum chamber for 30 min. The amorphous ITO:Ga (0.1 wt.% Ga) films post-annealed at 220 °C exhibited relatively low resistivity (4.622x10⁻⁴ Ω cm), indicating that the crystallinity of the ITO:Ga films decreased with increasing Ga content. In addition, the amorphous ITO:Ga films showed a better surface morphology, etchability and mechanical properties than the ITO films. - Highlights: • The Ga doped indium tin oxide (ITO) films crystallized at higher temperatures than the ITO films. • The amorphisation of ITO films increases with increasing Ga content. • Similar resistivity was observed between crystalline ITO and amorphous Ga doped ITO films. • Etching property of ITO film was improved with increasing Ga content