Oxidation behavior of (Ti,Al)N films at high temperatures under controlled atmosphere

• Main Authors: Jui-Hung Chen, 陳睿鴻
• Other Authors: 呂福興
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/37537249801584764399

碩士 === 國立中興大學 === 材料工程學系所 === 94 === The object of this research is to investigate oxidation behavior of (Ti,Al)N films annealed in the controlled atmophere. (Ti,Al)N films were reatively sputtered onto Si substrates (100) by cathidic arc ion-plating sputtering deposition. The films were then annealed in air, N2, forming gas (N2/H2=9), and vacuum. Annealing was conducted over temperatures beteween 300-1100℃ for 0.5-12 h. For all atmosphere except vacuum, colors of the films would turn from original sliver to sliver and gray, then become gray with increasing oxidation temperature. X-ray diffraction analyses show that appeared first and TiO2 then Al2O3 was formed. When annealed in vacuum, the color of the films remained unchanged and no oxide was found. Annealing in forming gas and vacuum at 900℃ caused the phase decomposition of (Ti,Al)N films and the resultant phase were TiN and AlN, which would be further oxided at higher temperatures. Besides, microstructure changes of the (Ti,Al)N films after annealing were investigated by using a field-emission scanning electron microscope. The surface morphology of as-deposited films was rather smooth and became particlulate after annealing. From the cross-sectional view original films revealed columnar structure. After annealing in above atmosphere except vacuum, the upper part of the films was dense while the lower part exhibited small-rod structures. The reason for that may be after annealing phase decomposition of the fims occured first, then the TiN was oxidized into TiO2. With increasing temperature, large crystals was also observed on the surface, which is due to volume expansion of TiO2 in the films. Residual stresses of the films were measured by X-ray diffraction after annealing in vacuum. Resideual stress of as-deposited (Ti,Al)N films was -3.52 GPa and became -5.14 GPa at 300℃. When annealing at higher temperatures residual stress was relaxed and became tensile, i.e., 0.31 GPa, at 1100℃.