Combined effects of substrate temperature and post annealing temperature on structural, optical and electrical properties of Sb-doped SnO2 films

Abstract

Sb-doped SnO2 (ATO) films have received extensive attention as transparent conductive films, but there is still a lack of in-depth and systematic study on combined effects of substrate temperature (Ts) and annealing temperature (Ta) on their transparent conductive properties. In this study, ATO films were prepared using RF magnetron sputtering at RT∼400 ℃ and subsequently annealed at 200–1000 ℃. The results show that the conductive properties of the films enhance (with a decrease in resistivity from 1.15×10-1 to 2.15×10-3 Ω•cm) and the average visible-light transmittance (TVis) decreases (90.16 → 38.24%) with increase of Ts. With the increase of Ta, the conductive properties of the films prepared at different Ts tend to first enhance and then degrade, and the TVis basically shows a trend of first decreasing and then increasing. After annealing at 600 ℃, the films prepared at RT and 100 ℃ can achieve better comprehensive properties (resistivity of 2.50×10-3 and 1.64×10-3 Ω•cm, carrier concentration of 3.35×1020 and 4.93×1020 cm-3, mobility of 7.73 and 7.76 cm2/V•s, sheet resistance of 84 and 55 Ω/sq., and TVis of 86.63 and 79.50%). In order to explore the intrinsic mechanism of the optical and electrical performance of ATO films changing with Ts and Ta, the preferred orientation, crystallinity, and stress state of the films were analyzed by XRD, and their surface morphology was observed by SEM. Meanwhile, the chemical states of Sn, O and Sb as well as Sb content in the films were analyzed by XPS, and their lattice vibration modes of the film were studied by Raman spectra. Finally, the process-structure-properties correlations were established for the ATO films.