以分子動力學研究含缺陷砷化鎵半導體之機械特性

Mechanical characteristics of gallium arsenide semiconductors with defects using molecular dynamics

黃進財(Chin-Tsai Huang)

指導教授 ： 方得華

國立虎尾科技大學/工程學院/機械與機電工程研究所/碩士(2009年)

摘要

摘要
本文利用分子動力學方法來研究含缺陷砷化鎵半導體材料在奈米尺度下壓痕和刮痕的變形機制及機械特性。在模擬過程中，探針與砷化鎵薄膜是以Tersoff勢能來描述原子間的作用力，其中探針保持為剛體。模擬的內容分成完美結構砷化鎵薄膜之壓痕及刮痕與含缺陷砷化鎵薄膜的壓痕及刮痕分析，並加以探討與比較。由壓痕模擬結果發現，當完美砷化鎵薄膜厚度增加，最大負載力與硬度會隨之降低，整體上會隨著壓痕深度的增加而上升。當完美結構與含缺陷結構相比，隨著缺陷直徑的增加會使壓痕最大負載力與硬度下降。在刮痕過程中，當刮痕深度增加時，剪切力與正向力會隨之增加。而完美結構與含缺陷結構相比，當缺陷原子增加會導致剪切力與正向力有遞減的趨勢。完美結構砷化鎵薄膜與含缺陷砷化鎵薄膜遭受壓痕與刮痕的影響，導致砷化鎵原子結構混亂，並產生大量的原子滑移現象。最後將探討砷化鎵薄膜機械性質實驗與模擬結果做一系列比較。

關鍵字

分子動力學 ； 砷化鎵 ； 奈米壓痕 ； 奈米摩潤學 ； 機械特性

並列摘要

Abstract
This study used molecular dynamics (MD) to investigate the deformation behavior and mechanical characteristics of gallium arsenide (GaAs) semiconductors with defects under nanoindentation and nanoscratch. In the simulation process, Tersoff’s potential was conducted to describe interatomic forces of GaAs films. The main content of simulation was analyzed the perfect and defects structure of GaAs films under indentation and scratch, and to compare each other. The indentation simulation results showed that when the perfect GaAs film’s thickness increased, the maximum load and the hardness were decreased, as well a whole indentation depth increased. Comparison the perfect GaAs structure and GaAs with structural defects, we found that the diameter of defects increased, the maximum load and the hardness of indentation were decreased. In the scratch process, when the perfect GaAs film’s scratch depth increased, the shear force and the normal force were increased. And the perfect structure and compared with structural defects, when the air role ratio of defect increased, the shear force and the normal force were decreased. The perfect and defects structure of GaAs films subjected to the effects with indentation and scratch, caused disordered structures around GaAs surface and had a slip phenomenon of a large number of atoms. Finally, MD simulation results would be compared with the experimental results to understand the mechanical properties of GaAs films.

並列關鍵字

molecular dynamics ； gallium arsenide ； nanoindentation ； nanotribology ； mechanical characteristic

參考文獻

參考文獻

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