Characterizations of Silicon Nitride and Tungsten Oxide Nanowires on Si (111) and Si (100)

• Main Authors: Mo-Tung Chang, 張睦東
• Other Authors: L. J. Chou
• Format: Others
• Language: en_US
• Online Access: http://ndltd.ncl.edu.tw/handle/r5by56

碩士 === 國立清華大學 === 材料科學工程學系 === 92 === Part 1 (Characterizations of The Epi-nitride) High-K dielectric materials have attracted much attentation due to the requirements for the shrinkage of the nano-electronic devices. In this study, single crystal silicon nitrides have been prepared by plasma enhanced MBE system, and investigated by the HREM analysis as well as C-V measurements. The d-spacing of this epi-film observed from HRTEM image along the c-axis is 13.8 % larger than the theoretical value in the bulk material. It shows that the c-axis of this epi-layer has been expanded due to the stress. It would effect the electric characteristics. The electric characteristics reveal that the electrons are the active carriers injected into the insulator at positive bias. The superiority of this study is that we can couple this unique epitaxial insulator to the mature silicon process. So that, the next generation MIS structure can be achieved. Part 2 (Characterizations of The Tungsten Oxide Nanowires) Tungsten oxide nanowires have been synthesized on the large scale silicon substrate in this study. The synthesized methods are described as the following. First, the clean 4 inch Si wafer with native oxide was loaded into the high vacuum chamber at a pressure of 3.0x10-8 mbar. The substrate was heated to 8000C and thermally treated in ammonia and tungsten vapor ambient for 20 minute. When the chamber cooled down to room temperature, the upper surface of the silicon substrate was entirely covered with a semi-transparent film. The nanostructure and morphology as well as composition characterization of the tungsten oxide nanowires were carried out and the plausible growth mechanism to explain our growth of the nanowires were proposed. Finally, the electron field emission property was examined to confirm the potential application as the FE emitter device. The PL spectrum of these products shows the green peak 470 nm due to the oxygen defect. The superiority of the process is the combination of the nano-technology and existed silicon industry. These nano-products have great potential for application of nano-device.