【作者】 郝鹏；

【导师】 杜丕一；

【作者基本信息】 浙江大学 ， 材料学， 2006， 硕士

【摘要】 跨入21世纪随着平板显示技术（FPD）飞速发展,需要更低电阻率的材料作为FPD薄膜晶体管的接触电极,以提高响应速率、降低功耗。传统的场致发射平板显示器（FED）的微尖锥场发射体制作成本高、易与环境气体反应,限制了其工业化。采用低成本的方法在玻璃上制备高导电性的硅化钛薄膜并在薄膜层上生长纳米线能够有效的解决这些问题,极大的推动平板显示技术进一步发展。 本论文采用常压化学气相沉积法（APCVD）以SiH₄和TICl₄为前驱体在玻璃衬底上一次性制备出大面积硅化钛薄膜/纳米线复合结构,运用XRD、SEM、TEM、EDX、四探针电阻仪、紫外可见光谱仪等手段对样品的结构和性能进行了测试和分析。讨论了薄膜中晶相的形成过程和机理,以及薄膜层上纳米线的形成和生长机理。成功实现了硅化钛纳米线在相应薄膜层上的生长。 结果表明,APCVD法在玻璃基板上沉积低电阻硅化钛（TiSi₂）薄膜的过程由前驱体SiH₄和TiCl₄的化学反应控制。通过调制前驱体不同的反应进程,使生成TiSi₂的化学反应在沉积过程中为主导,促进薄膜中TiSi₂晶相的形成,从而得到电阻率较低的薄膜,典型样品的电阻率为37μΩ·cm。TiSi₂薄膜在玻璃基板上的形成过程是,SiH₄和TiCl₄在气相反应直接形成TiSi₂晶核,而后沉积在玻璃衬底的表面,随着沉积时间的延长,晶粒逐渐长大,堆积变得致密,结构也趋于完整,薄膜的电阻率也随着降低。通过控制前驱体不同的化学反应,提高低阻相TiSi₂的在薄膜中的含量,降低薄膜电阻率,可以得到红外高反射率的薄膜。 APCVD法成功的在玻璃基板上一次性制备出大面积硅化钛薄膜/纳米线复合结构,实现了高质量、高密度的硅化钛纳米线在薄膜层上的生长。正交晶系的TiSi方形纳米线（RNWs）截面为矩形,长约几微米,宽、高介于20-40nm,生长方向是[011]。纳米线以气/固模式生长,TiSi₂薄膜沉积完成后,控制残余前驱体SiH₄和TICl₄的反应,使新相的纳米岛在TiSi₂薄膜中的颗粒上形成,在TiSi纳米岛的自诱导作用下,TiSi晶体开始生长,此后为保持较低的表面能,晶体结构的各向异性使TiSi在（011）晶面上优先生长,最终导致了沿[011]方向生长的TiSi方形更多还原

【Abstract】 The Flat Panel Displays （FPDs） are rapidly developing in 21st century. Novel materials with the lower resistivity are required for contact electrodes of the FPDs to enhance the respond performance. Besides, Fabrication of the field-emitters of Field Emission Displays （FEDs） is too complex to step forward. The combination of conductive thin films and nanowires deposited on large area glass by simple methods with low cost will solve the above problems.In this thesis, the films and nanowires of titanium silicides were prepared on the glass substrate by atmosphere pressure chemical vapor deposition （APCVD）, using SiFLt and TiCl₄ as precursors. XRD, FESEM, EDX, UV-VIS spectrometer and Four-point probe were employed to characterize structure and properties of the films, respectively. The phase formation in the films and CVD reaction were studied. The formation and growth of TiSi nanowires were also clarified.The results reveal that the deposition of the films is determined by CVD reaction between SiH₄ and TiCl₄.Via controlling the CVD reaction to promote the TiSi₂ formation and depress the Ti₅Si₃ formation at the same time, the TiSi₂ films can be gained with the low resistivity. The mechanism of the films deposition is described as below: SiFLt and TiCl₄ directly reacted in the vapor phase at first, and then the TiSi₂ grains deposited on the glass substrate. The stack density of the TiSi₂ crystalline phase gradually increased and the particles grew up. The films came to continuous and uniform, resulting in the low resistivity. The infrared reflection relys much on the phase formation in the films. Improving the concentration of the TiSi₂ crystalline phase, decreasing the sheet resistance will enhance of the infrared reflection of the TiSi₂ films.The TiSi crystalline nanowires with the orthorhombic structure were prepared on the TiSi2 films deposited on glass substrate. The length of the nanowires is more than several micrometers with the width between 20nm and 40nm. The growth direction is [011]. The growth process involves the self-induced growth of TiSi nanowires via the ’vapor-solid’ （VS） growth mode. In the initial stage, the TiSi crystalline nanoislands are formed on TiSi2 particles. After that, an intrinsically anisotropic crystallographic structure of the TiSi crystalline results in the growth along [011] direction of nanowires. The silicide nanoneedles, core-sheath nanowires are also prepared by APCVD.Moreover, nanowires and films of titanium silicides are also prepared on Si （111） substrate. The nanowires growth on films is not affected by underlying substrate.更多还原