以分子動力學模擬鈷團簇原子沈積於矽基板之研究

Molecular Dynamics Simulation of Co Cluster Deposition on Si Substrate

賴韋志(Wei-Jhih Lai)

指導教授 ： 陳興松

國立虎尾科技大學/工程學院/材料科學與綠色能源工程研究所/碩士(2014年)

摘要

本研究是利用分子動力學方法模擬鈷團簇原子沈積於矽積板，探討薄膜沈積之後的形貌以及微觀結構的變化。模擬的方法是以Tight-Binding多體勢能函數描述鈷對鈷及鈷對矽之勢能，而以Tersoff勢能函數來計算矽對矽分子間的作用力，研究是以改變鈷原子之入射能量、基板溫度以及鈷團簇原子數量為變數等進行沈積的模擬，此外本文也以原子轟擊的方式進行模擬與討論，並藉由Gear五階預測修正法計算系統中原子因外力而產生的位移及其位置、速度與加速度。
由模擬的結果發現：入射能量與基板溫度越高混合情形越明顯，同時殘留應力也會變大。適當的提高入射能量及基板溫度可有效的降低薄膜表面粗糙度，但入射能量太高則會導致轟擊情況嚴重，造成基板的破壞，導致表面粗糙度上升;團簇原子數則反之，其原子數越多粗糙度越高。經由薄膜表面形貌可發現，團簇原子於低能量入射時會以島狀結構成長，團簇原子數越多島狀形貌也越明顯，可藉由基板溫度或入射能量的上升使島狀形貌趨於平坦。此外於原子轟擊時，入射能量越高於基板表面所形成之火山孔形貌會越明顯。

關鍵字

分子動力學 ； 團簇沈積 ； Tight Binding多體勢能 ； Tersoff多體勢能 ； 殘留應力

並列摘要

In this study, we used molecular dynamics simulation method for Co clusters deposition on Si substrate, we discuss the change of morphology and microstructure after the thin film deposition. TB-SMA many-body potential was used to describe the interaction of Co-Co and Co-Si, Tersoff many-body potential was used to describe the of Si-Si atomic interaction. Different values of incident energy, substrate temperature, atomic bombardment and cluster size were investigated，and by Gear fifth-order predictor corrector method to calculate the atom due to an external force displaced position, velocity and acceleration.
Results indicated that increasing the substrate temperature and incident energy could increase the mixing condition, at the same time. the residual stress will be increased to positive. Increasing the incident energy and substrate temperature helps to reduce the surface roughness, but the incident energy was increased too high for the bombardment condition becomes more serious, while high incident energy will damage the substrate to increase the surface roughness. In the aspect of cluster size, increasing the cluster size could make the surface roughness rise. Pass through the surface morphology of thin films can be found, low incident energy will be the island growth in cluster atoms, increasing the cluster size helps to become more obvious in the island morphology, increasing the incident energy or substrate temperature helps to reduce the island morphology. Finally, In the atomic bombardment, the more incident energy, the more obvious of volcano pore morphology.

並列關鍵字

molecular dynamics simulation ； cluster deposition ； Tight Binding potential function ； Tersoff potential function ； residual stress

參考文獻

[46] 陳冠宏，分子動力學模擬原子轟擊之物理機制研究，國立高雄應用科技大學模具工程系碩士班，(2011)。

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