Controlling Defect Creation and Optimizing Carrier Density of Ga Doped ZnO Films via Sputtering Deposition Using a Zn Added Target

Ga‐doped zinc oxide (GZO) films are deposited on quartz substrates at ambient temperature via magnetron sputtering using a Zn‐added GZO powder target. The addition of Zn results in a significant increase in carrier density compared with that of the films deposited without adding Zn and a decrease in film resistivity to 4 × 10 −4 W cm. Additionally, it eliminates the in‐plane spatial distribution of the GZO‐film electrical properties; this distribution is observed when using a conventional sputtering target. Furthermore, the addition of Zn reduces the variation in the GZO‐film electrical properties with the T–S distance, exhibiting only a small increase in film resistivity at long T–S distances. The effect of adding Zn to a sputtering target indicates that the degradation in the GZO‐film electrical properties is mainly caused by the deficiency of Zn in the GZO crystals. The variation in GZO‐film thickness with the T–S distance shows an abrupt decrease in carrier density for small thicknesses, indicating the presence of acceptor‐like defects in the vicinity of the substrate/GZO interface; these defects cannot be eliminated by adding Zn.