UV雷射於氟摻雜氧化錫薄膜退火製程之研究

Abstract

本研究使用UV雷射加工系統對FTO透明導電薄膜進行退火，探討不同雷射退火參數對薄膜特性之效果。藉由調整不同加工參數，包括雷射離焦光斑尺寸、雷射能量及振鏡掃描速度，分析其對於薄膜的表面形貌、電性、機械特性和光穿透性的影響。退火後薄膜表面性質分析藉由原子力顯微鏡(AFM)觀察薄膜表面粗糙度、掃瞄式電子顯微鏡(SEM)觀察薄膜表面形貌、奈米壓痕儀器量測機械特性(微硬度和彈性模數)、霍爾量測儀分析薄膜電性和電阻率變化情形與分光光譜儀量測光穿透率。實驗結果得知，調整離焦直徑為1 mm、雷射能量為164 µJ和固定掃描速度為800 mm/s時，獲得最佳的薄膜電阻率從1.26x10-2 Ω-cm降低至6.17x10-3 Ω-cm，且退火後FTO薄膜/玻璃基板可見光平均穿透率從81.2%提升至86.4%。奈米壓痕量測結果顯示，隨雷射能量提升退火作用下，薄膜微硬度呈現略微上升的趨勢，彈性模數呈現略微下降的趨勢。從SEM觀察結果發現，薄膜晶粒大小隨著退火雷射能量提升而變大。從AFM量測結果獲得，薄膜表面粗糙度隨著退火雷射能量提升而有些微增大。

The effects of post-annealing on structural, electrical, mechanical, and optical properties of the fluorine-doped tin oxide (FTO) thin films by ultraviolet (UV) laser irradiations were investigated in this study. The annealing process parameters such as laser energies, scan speeds of scanning galvanometer, and spot sizes of defocus laser fabricated at an ambient temperature were adjusted. The surface morphology and roughness of annealed films were observed by a scanning electron microscope (SEM) and an atomic force microscope (AFM), respectively. Moreover, the electrical and mechanical properties were measured by a hall instrument and a nanoindentation, respectively. The optical properties of transmittance were measured by an UV-VIS spectrophotometer. Under optimized laser annealed conditions including 1 mm of spot size, 164 µJ of laser energy, and 800 mm/s of scan speed, the resistivity of the annealed film was reduced from 1.26x10-2 Ω-cm to 6.17x10-3 Ω-cm, and the average optical transmittance of the annealed FTO/glass substrate was enhanced from 81.2% to 86.4% in the visible range. In addition, the microhardness and reduced modulus of these annealed FTO films slightly increased and decreased with increasing the laser energy measured by the nanoindentation. The SEM observed images showed that the grain sizes of annealed FTO films increased with increasing the laser energy. Furthermore, the AFM measured results showed that the surface roughness of annealed FTO films slightly increased with increasing the laser energy.