Nanoindentation Behaviour and Annealed Microstructural Evolution of Ti/GaAs Thin Film

• Main Authors: Chung-ChiaLo, 羅崇嘉
• Other Authors: Woei-Shyan Lee
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/x528c6

碩士 === 國立成功大學 === 機械工程學系 === 105 === 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.