ZnO薄膜的粉靶溅射沉积

The Deposition of ZnO by Using Powder Target

氧化锌是一种重要的压电与光电材料,用粉靶代替常规的固体陶瓷靶溅射沉积ZnO薄膜,对基底的加热温度、溅射气压和氧气的混合比率等沉积条件对氧化锌薄膜特性的影响进行了研究,主要对沉积在玻璃基片上的ZnO薄膜进行了X-射线衍射(XRD)、扫描电镜(SEM)、原子力显微镜(AFM)以及台阶仪的测量和分析比较,用粉靶溅射的ZnO薄膜具有很好的C轴长相和很窄的衍射峰半宽(0.2°～0.27°)。因为ZnO膜在C轴方向有很强的压电性,从而也说明了用粉靶溅射的ZnO薄膜具有很好的压电特性。分析和测量结果显示用粉靶溅射ZnO薄膜的最佳条件是:(1)基片加热温度为300～400℃。(2)氧气的混合含量为0.5～0.8.(3)溅射气压为1～2 Pa。得出了利用粉靶溅射制备的ZnO薄膜与用陶瓷靶制备同样具有很好的性能。

ZnO is a kind of new piezoelectric and optoelectronic material for its excellent properties. We deposit ZnO thin films by RF magnetron sputtering system. In our sputtering deposition of ZnO thin films, a pure ZnO powder target is used instead of the conventional hot-pressed ceramic disk target. By using the pure ZnO powder target, the influences of sputtering conditions are studied. The growth temperature is from 200℃ to 500 ℃ , the total sputtering gas pressure is changed from 1 Pa to 5 Pa, and the concentration of O2 from 10% to 100%. The sputtering power in all the cases is 80 W and all the samples are cooled in the chamber, in 10-4 Pa after deposition. We measure and analyze the sputtered ZnO thin films first by X-ray diffraction, The X-ray diffraction graphs display the narrow diffraction line width (0.20°-0.27°), which shows the ZnO thin films with highly c-axis orientation. The lattice constant in c-axis is in the range of 5.20-5.25 A. Then a scanning electron microscope (SEM) is used. The SEM pictures show that the surface is smooth and uniform ZnO grains in the thin films, which consist of nanoscaled particles (25-60 nm). We also use the atom force microscope (AFM) to study the ZnO thin films and compare them with the pictures obtained by SEM. Both have the same suits. The surface profiler is also used to measure the thickness of the ZnO thin films. It is shown that the deposition rate is in the range of 1 000 - 2 500 A/hr. According to the above measurements and analyses, the optimized sputtering conditions for depositing high c-axis orientation with smooth surface of the ZnO thin films in the powder target case are: (1) thesubstrate temperature is from 300-400℃ (2) the ratio of O2/(O2 + Ar) is frem 0.5-0. 8. (3) the total sputtering gas pressures is from 1-2 Pa. In general, by RF magnetron sputtering system the powder targets can provide the sputtered ZnO thin films with high deposition rate, excellent c-axis orientation with uniform grains. In some case, by using the ZnO powder target with high power, the deposition rate of the films is higher than 1 μm/h, the c-axis orientation is very excellent, and the surface is also smcotalso smooth.