- 學位論文
以熱退火處理金薄膜成長於 SiO2 / Si 之表面形貌變化
Surface Morphology of Annealed Gold Films Grown on SiO2 / Si Substrates
摘要
本研究以熱蒸鍍法的方式，蒸鍍 30 nm 金薄膜於有或無二氧化矽層厚度的 (100) n - type 矽基板上，在以熱退火 (Thermal Annealing) 的方式處理過後，奈米金薄膜表面形貌會產生變化。隨著溫度的提高，金薄膜為了減少系統的總表面能進而減少表面積，以此驅使金薄膜形成島狀。從 AFM (Atomic Force Microscopy) 及 SEM (Scanning Electron Microscopy) 的量測結果可以發現，金薄膜成長於有或無氧化層矽基板在熱退火後，形成島狀時的溫度以及形貌會有所不同。無氧化層矽基板上的金薄膜總體積也會相對於有氧化層矽基板上的金薄膜有所減少。 我們推測，金薄膜在沒有二氧化矽層的阻擋下成長於矽基板上後在經過熱退火處理時，金與矽的直接接觸可能會有金 — 矽共晶合金及矽金化合物的產生，進而影響表面形貌。而在共晶狀態時，則會因為金與矽的比例不同而使凝固點不同，造成從液態凝固到固態時發生相分離，使形成的島狀會有矽的元素，也會有部份的金沉浸到基板表面裡。進一步以 EDS (Energy Dispersive X-ray Spectrometer) 檢測熱退火後形成的島狀結構可以發現，金與矽的比例會有所不同。而從 XPS (X-ray photoelectron spectroscopy) 的結果可以確認去氧化層矽基板在熱退火溫度 800 ℃ 會有矽金化合物的產生。
並列摘要
In this study, we deposited 30 nm thick gold thin films on n-type (100) silicon substrates. After thermal annealing, the surface morphology of the gold films was changed. As heating, the collective surface area of the gold films would decrease to reduce the total surface energy of the system, so that the gold films changed into island-like shapes. From the results of AFM (Atomic Force Microscopy) and SEM (Scanning Electron Microscopy), the samples on two kinds of silicon substrates (covered with silicon dioxide layer or not) showed different morphologies after annealing. Their responses to annealing temperatures were also different during the annealing process. We speculated that the gold-silicon eutectic alloy and gold silicide might form in the direct contact between the gold and silicon when the gold films were grown on the bare silicon substrates and thermal annealed. This formation also affected the surface morphology. In the eutectic state, the different proportions of gold and silicon caused different melting points, resulting phase separation when the liquid phase solidification occurred. Therefore the island-like formations contained silicon element. Some gold also immersed into the silicon substrates. Further, the island-like structures formed after thermal annealing was investigated by EDS (Energy Dispersive X-ray Spectrometer). The ratio of gold to silicon was found to be different. As a result of XPS (X-ray photoelectron spectroscopy), it was confirmed that the samples on bare silicon substrates had gold silicide formations at a thermal annealing temperature of 800 ℃.