The effect of local defect on thin film mechanical properties is studied in this thesis. The molecular dynamics (MD) is employed to simulate and analyze the relation between intermolecular strength and deformation in the nanoindentation test. The variation of hardness and elastic modulus are simulated from the load-displacement response and the projected area of contact at the maximum load. In this study, Tersoff potential function is employed to describe the molecular behavior of nano-scale carbon and silicon films. The MD models of the diamond indenter and film are applied in the simulation. Due to the hardness different, the diamond indenter can be assumed rigid when silicon thin film was test. However, the indenter¡¦s wear and compressive effects can not be ignored when diamond film were studied under nanoindentation simulation. The indentation parameter in the simulation includes substrate size, indentation velocity, peak hold time, system temperature, indentation depth, local void size, void position and vacancy rate. The results show that the hardness and elastic modulus of thin film may decrease significantly with considering the existence of local defect. The results also elucidated that the elastic modulus and hardness for perfect lattice structure thin films should be the upper bond value of the real bulk material.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0728109-110418 |
| Date | 28 July 2009 |
| Creators | Huang, Chiung-yu |
| Contributors | Yung-chuan Chen, Shyh-chour Huan, Der-min Tsay, Jao-hwa Kuang, Ying-chien Tsai |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0728109-110418 |
| Rights | campus_withheld, Copyright information available at source archive |
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