磁控溅射低温制备ZnO∶Al透明导电膜及其特性研究

Growth and Properties of Transparent Conductive ZnO∶Al Films by Magnetron Sputtering at Low Temperature

采用锌、铝(Al 2 wt.%)合金靶,真空腔温度保持在50℃,运用直流反应磁控溅射法制得系列的ZnO∶Al(ZAO)薄膜。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、分光光度计、半导体霍尔效应测试、红外发射率测试仪等手段对薄膜进行了表征。薄膜呈C轴择优取向的六角纤锌矿结构;具有致密平滑的表面形貌;最佳工艺下样品在550 nm波长处透过率达93%;最低电阻率为4.99×10-4Ω.cm;8μm^14μm波段平均红外发射率在0.3~0.54之间。分析了溅射过程中氧流量百分比和功率对上述特性的影响及各特性间的关系,讨论了薄膜在8μm^14μm波段平均红外发射率与其方块电阻的关系。

Al doped ZnO（ZnO-Al） films were grown by DC reactive magnetron sputtering on glass substrate at a vacuum chamber temperature of 50 ℃. The films were characterized with X-ray diffraction（XRD）, scanning electron microscopy （SEM）, spectroscopy, Hall-effect measurement, and infrared radiometer. All films, fairly smooth and compact, are found to have hexagonal wurtzite structure with c-axis as the preferential growth orientation. The results show that the percentage oxygen flow rate and the sputtering power significantly affect the microstructures and properties of the films. For example, as the percentage oxygen flow rate increases, its resistivity first decreases and then increases, minimizing 4.99 × 10^-4 Ω·cm at 12% ;and its conductivity improves with an increase of the sputtering power;the highest cartier density can be 8.99 × 10^20 cm^-3 at 75 W, mid the averaged infrared emissivity in 8 μm- 14 μm range is found to be 0.3 - 0.54. Under optimized growth conditions, its optical transmittance can be 93% at 550 nm in the visible range. Dependence of infrared emission on the sheet resistance was also discussed.