【作者】 王健；

【导师】 吴雪梅； 诸葛兰剑；

【作者基本信息】 苏州大学 ， 微电子学与固体电子学， 2007， 硕士

【摘要】 本论文研究了SiC薄膜制备以及光电发射性质,并且讨论了在脉冲栅控行波管中SiC薄膜涂层对抑制栅极电子发射影响,以及薄膜涂层在高温栅网表面的物理化学性质以及结构的变化,探索薄膜系统的工作机理。在样品制备过程中,利用射频（RF）磁控溅射复合靶技术和N2气氛保护高温退火的后处理方法,在Mo衬底上制备出了碳化硅（SiC）薄膜,为了仿真现实行波管的工作背景环境,采取化学方法在薄膜表面沉积BaO,并且使用拉曼发光谱（ Raman）、扫描电子显微镜（SEM）、X射线衍射（XRD）等测量手段,研究了薄膜在973K到1273K的不同温度退火时候薄膜的结构、形貌以及光电发射等性质。同时对于SiC涂层抑制行波管栅极电子发射能力的影响,结果表明BaO/SiC/Mo系统高温退火后能够有效的去除栅网中的BaO的沉积玷污,结合XRD的实验结果以及吉布斯函变的计算研究分析样品表明温退火后样品表面的BaO与Si,C的不饱和键易于反应消除其低功函数的影响提高样品的功函数,并且最终的反应产物SiC和SiO₂均为高功函数的物质。从而论述SiC薄膜抑制行波管的栅电子发射的机理。更多还原

【Abstract】 Pulsed-controlled grid traveling wave tubes become the key components in the national defenses, modern weapon, and navigation in the space and GPS system. It is also especial importance to prolong the working life of tubs for its short function period. In this paper, we discuss the preparation and photo-electron emission character of SiC thin film by the measurement of the Raman Spectrum (Raman), Scanning electron microscopy (SEM), X-ray diffraction (XRD) etc. Furthermore we research the structure and phase change of molybdenum grid coated with silicon and carbon composite thin films under high temperature. And the effect that si-c composite thin film has on the suppressing grid emission in pulsed-controlled grid traveling wave tubes has been studied.Si-C composite thin films were deposited on molybdenum grids by radio-frequency magnetron sputtering technology from the silicon and carbon composite target. The as-deposited films were annealed in the temperature range from 973K to 1273K. In order to simulate the working conditions of the grids contaminated by BaO from the activation of hot cathode in Pulse-controlled grid traveling-wave tubes (TWTs). BaO layers were deposited on the surface of the as-deposited thin films by the chemical method. The compositional and phase change of the samples were investigated after annealing from 973K to 1273K.The structure and phase change of BaO/Si-C/Mo systems under high temperature are discussed according to the experimental results and the calculation of the reaction free energy. The results indicate that graphite and silicon on the surface of Mo grids can prevent BaO from accumulating on the grid surfaces. SiC (about 4.4eV) and SiO2 (about 3.1eV) with high work function are the last products on the surface of Mo grids. Therefore, the silicon and carbon composite thin films deposited on the Mo grid surface can effectively suppress the grid electron emission.更多还原