Combination of Chemical Vapor Deposition and Atomic Layer Deposition Method for Pt-Ru Catalyst Deposition on Si(111) Substrate

• Main Authors: Sriana Tun, 史安菟
• Other Authors: Lu-Sheng Hong
• Format: Others
• Language: en_US
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/03557303134725953357

碩士 === 國立臺灣科技大學 === 化學工程系 === 97 === Pt-Ru alloy can be produced with some methods. One of these methods is applying thin film technology. The aim of this research is to find the reaction zone of depositing Pt-Ru alloy catalyst by atomic layer deposition (ALD) method. Before using ALD method, the reactions of Ru precursor on various substrates were studied by chemical vapor deposition (CVD) method to understand the baseline of Ru-CVD. Then, we applied the baseline condition of CVD method to investigate the ALD growth regime. On the other hand, we investigated the Pt deposition by ALD method using hydrogen as the reactive gas. Finally, we tried to combine CVD and ALD method for the deposition of Pt-Ru binary catalysts on Si(111) substrate. Ru catalyst deposition by CVD method, the different regimes of reactions kinetics were taken place on different substrate, which resulted in different morphology of Ru catalyst by using bis(ethylcyclopentadienyl) ruthenium as precursor. Since Ru depositions were controlled by adsorption of precursor, Ru catalysts were more difficult applied by ALD method than by CVD method. The hydrogen was used as the reactive gas to react with trimethylcyclopentadienyl platinum for Pt ALD. Close to 1 ML deposition of Pt can be achieved at substrate temperatures of 300 and 350oC. 2s exposure time of purge obtained good result for 4s exposure time of precursor but not enough when exposure time of precursor was increased to 6s. Increasing exposure time of hydrogen as the reactive gas resulted in a quite low growth rate because the hydrogen would remove the precursor, though they might not react to each other. Combination of Ru CVD and Pt ALD methods applied in DMFCs using oxygen as reactive gas gave the better performance compared with using hydrogen gas. Moreover, the CO poison of Pt catalysts can be eliminated by the combination of Ru CVD and Pt ALD methods.