本研究主要討論鈦/砷化鎵薄膜系統奈米壓痕行為以及退火後薄膜界面化合物形成對機械性質變化。本實驗首先利用電子束蒸鍍法在砷化鎵晶圓上製作一100 nm厚度之鈦薄膜，選取並切割實驗試片後，以奈米壓痕系統對未退火試片進行50 nm及200 nm深度之奈米壓痕試驗，以瞭解壓痕深度對薄膜系統機械性質之影響。另外一組試片經過退火處理，條件為加熱至490℃，並持溫36分鐘，再對試片進行50 nm、120 nm以及200 nm深度之奈米壓痕試驗，藉以比較未退火及退火後，化合物形成對微觀機械性質之改變及影響。
巨觀機械性質量測顯示，硬度受壓痕尺寸效應與表面粗糙度及基材效應所影響，薄膜硬度值約為7.84GPa，楊氏模數約為118.90GPa。負載-深度曲線顯示在壓痕深度200nm時，曲線有pop-in的現象發生，其原因為基材內部產生差排滑移的現象，由穿透式電子顯微鏡可觀測到此結果。退火後微觀結構可發現界面形成兩種化合物，由其晶格間距可證明為Ti2Ga3以及TiAs。穿透式電子顯微鏡觀測結果顯示，在壓痕深度200nm亦有差排產生，但負載-深度曲線並無pop-in現象發生，可證明其差排成因為基材內部雜質或空洞所致，基材並無明顯差排滑移現象產生。

The mechanical properties of Ti/GaAs thin films in room temperatures and annealed indented to different depth are investigated by using a nanoindentation technique. The specimens are annealed at the temperature 490℃ for 36 minutes. After annealed, Ti/GaAs thin films become to Ti2Ga3/TiAs/GaAs layer and the evidence can prove by transmission electron microscopy (TEM). In addition, the Ti2Ga3 layer in the annealed specimens were analysed using Raman scattering spectroscopy. The result show that the pop-in effect appeared at the load-depth curve in the nanoindented depth 200nm in RT. The load-depth curve continuous and smooth after annealed. The hardness and Young’s modulus of the Ti/GaAs thin films have the values of 8.9GPa and 124.01GPa at the indentation depth of 200nm. After annealed, the values rise to 10.44GPa and 124.3GPa. The formation of dislocation detected by TEM can be the reason of the pop-in effect found in the condition nanoindented depth 200nm at RT. The dislocation also detected in the annealed specimens although the load-depth curve have no pop-in effect. The dislocation is related to the density of native defects and the difference in doping.

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