Study on Characteristics of ZnO:Ti thin films

• Main Authors: Jen-Chi Chao, 趙仁淇
• Other Authors: 汪芳興
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/87807436978474799050

碩士 === 國立中興大學 === 電機工程學系所 === 97 === This study employed the RF (13.56 MHz) Magnetron Sputtering System to investigate electrical and optical properties of TZO thin-films, for optoelectrical applications. By using argon as the sputtering gas medium, the electrical, optical, and structural properties of TZO thin-films were analyzed by varying the thickness of the film and the substrate temperature. The substrate temperature was raised from room temperature to 300 °C and the film thickness was varied from 30 nm to 950 nm at a working pressure of 5×10-3 Torr and RF power of 100 W. The optimal parameters were at substrate temperature of 300 °C, and 330 nm film thickness, which resulted in an average light transmittance of 84% and a resistivity of 3×10-3 Ω-cm. Following the sputtering step, two post-treatments were performed. The first post-treatment annealed the thin-film in hydrogen atmosphere with the annealing temperatures of to 300 °C, 400 °C, and 500 °C for one hour. Next, the annealing time was varied from 30 to 90 min at 300 °C using different annealing gases such as Ar, H2, and Ar+ H2 (3:7). For the case of annealing at 400 °C and under hydrogen atmosphere resulted in an optimal resistivity of 1.29×10-3 Ω-cm and an average light transmittance of 85.6%. The second post-treatment used plasma treatment with different gases such as Ar, H2, and Ar+ H2. Hydrogen plasma was applied from 30 to 90 min with 10-120W (RF power), substrate temperature of 300 °C, and working pressure of one Torr. The optimal resistivity of 1.13×10-3 Ω-cm was obtained by using Ar+ H2 plasma treatment with a 83.2% average light transmittance. In this work, we compared the effect of post-annealing and plasma treatment on the optical and electrical properties of sputtered TZO thin-film as possible photoelectric devices. By employing the post-annealing step, light transmittance was enhanced, due to alteration of crystal structure, but the resistivity was less improved than that of plasma treatment. In contrast, the plasma treatment offered higher reduction in resistivity. However, due to bombardment of plasma gas ion on the film, the surface became rough, which scatter the light causing a slight reduction in light transmittance.