本研究主要探討二氧化鈦/砷化鎵薄膜系統奈米壓痕行為，以及退火
前後機械性質、表面形貌和微觀結構之變化。首先利用共濺鍍機於砷化
鎵基板上沈積200nm 及300nm 之二氧化鈦薄膜，分別對薄膜厚度200nm
試片進行150nm 和250nm 深度之壓痕試驗，以及薄膜厚度300nm 試片進行250nm 和350nm 深度之壓痕試驗，以了解壓痕深度與膜厚對機械性質及為結構之影響。此外也對另一組試片進行300℃持溫3 小時之加熱，同樣進行上述之量測，以比較退火前後機械性質與微觀結構之差異。實驗結果顯示，退火後之負載-深度曲線有pop-in 之現象，經退火後硬度及楊氏模數皆上升，與一般材料退火處理後，硬度與彈性模數之降低有所不同。利用TEM 照射薄膜的結構，發現經退火製程，薄膜從非晶系轉變結晶系，造成機械性質上升之結果。觀察試片表面形貌及剖面微觀結構可發現，退火後硬度及脆性提升，壓痕表面產生裂痕，而剖面結構則觀察到產生分離之現象，這是薄膜硬度遠高於基板硬度所造成之
buckling現象。

The mechanical properties of TiO2/GaAs thin films with and without annealing indented at room temperatures of different depth were measured by using a nanoindentation technique. The specimens were annealed at the temperature 300℃ for 3 hours. The result show that the pop-in effect appeared at the load-depth curve randomly for the annealed specimen indented at room temperature. The delamination of the thin film from the substrate were also observed. After annealing,the load-depth curve become not smooth and both the hardness and Young’s modulus were found to increase. Furthermore,dislocations density increased significantly as the indentation depth is increased. The changes in microstructure and mechanical properties were also discussed in terms of annealing, indentation depth and thickness of the thin film

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