MPCVD法制备高取向金刚石膜及设备改进的研究

发布时间：2018-04-22 03:06

本文选题：微波等离子体 + 化学气相沉积　；参考：《武汉工程大学》2015年硕士论文

【摘要】：CVD金刚石膜具有优异的物理化学性能,在多个领域有广阔的应用前景。目前,微波等离子体化学气相沉积方法以众多优点被认为是制备高质量高取向CVD金刚石膜的首选方法。本论文在实验室前期研究的基础上,利用韩国Woosinent公司R2.0-MPCVD装置以及实验室自制的10k W-MPCVD装置,系统研究了各项工艺参数对高取向金刚石膜的沉积研究,并对10k W圆柱形多模腔式MPCVD装置进行了合理的改进,使其符合沉积高质量取向CVD金刚石膜的要求。本论文具体工作如下:1、在韩国Woosinent公司R2.0-MPCVD装置上,系统研究了形核密度与氢等离子体处理对制备高取向金刚石膜的影响。发现在合适的工艺参数条件下,金刚石薄膜的表面形貌表现出很好的致密度和结晶度。随着沉积时间的延长,形核密度较高的金刚石膜也可获得111取向,形核密度较低的金刚石膜可获得偏向于110生长的取向且二次形核率相对较低。同时在沉积气压和基片温度较低的情况下,进行氢等离子体处理得到的晶粒明显增,明显改善金刚石薄膜的质量。2、在实验室自制的10k W新型MPCVD装置上系统研究了基片温度与甲烷浓度对微米级金刚石膜表面形貌可控性生长的影响。通过实验结果发现在当基片温度一定时,甲烷浓度的变化可能会对金刚石膜的取向,质量,形核密度和生长速率等产生重大影响。在温度一定的情况下,甲烷浓度越高金刚石膜的生长由111取向向100取向转变。金刚石膜的质量随着甲烷浓度的降低而逐渐升高。在甲烷浓度为2.0%前提下,从780℃到940℃表面形貌差别不大,这种现象表明在甲烷浓度适中时,金刚石膜的表面形貌对基片温度并不敏感。同时这种现象也表明,在中等浓度的甲烷浓度下,制备高取向金刚石膜的工艺参数有较宽的选择范围。3、根据实验中遇到的实际问题,对现有的10k W-MPCVD装置进行了改进。具体对天线结构,水冷系统以及腔体内的气流分布进行了合理的改进。首先将难于加工的喇叭型结构改成了垂直型结构获得了稳定的大尺寸等离子体球。其次对装置的水冷系统进行了改进,对水冷基片台进行了分区域水冷,使基片台中央区域至边缘区域的水冷效果逐渐降低,从而使基片上获得更为均匀的温度分布。最后对腔体内的气体流向进行了改进,使反应气体能更多的流经等离子体区,提高反应气体的利用效率。通过上述研究,掌握了在该新型10k W-MPCVD装置上各个工艺参数对CVD金刚石膜的沉积的一般规律,为高取向高质量CVD金刚石膜的制备提供了很好的实验基础。同时,通过对装置进行进一步改进并成功放电。为深入研究高质量高取向金刚石膜提供了新的优秀平台。
[Abstract]:CVD diamond films have excellent physical and chemical properties and have broad application prospects in many fields. At present, microwave plasma chemical vapor deposition (MPCVD) is considered to be the preferred method for the preparation of high quality and high orientation CVD diamond films with many advantages. Based on the previous research in laboratory, the deposition of highly oriented diamond films by various process parameters has been studied systematically by using the R2.0-MPCVD device of Woosinent Company of Korea and the 10k W-MPCVD device made by the laboratory. The 10kW cylindrical multimode cavity MPCVD device is improved to meet the requirements of high quality oriented CVD diamond film deposition. The effects of nucleation density and hydrogen plasma treatment on the preparation of highly oriented diamond films have been systematically studied in the R2.0-MPCVD plant of Woosinent Company, South Korea. It is found that the surface morphology of diamond films shows good density and crystallinity under the appropriate technological parameters. With the increase of deposition time, the diamond films with higher nucleation density can also obtain 111 orientations, and the diamond films with lower nucleation density can obtain the orientation which is inclined to 110 growth and the secondary nucleation rate is relatively low. At the same time, under the condition of low deposition pressure and substrate temperature, the grains obtained by hydrogen plasma treatment increased obviously. The effect of substrate temperature and methane concentration on the controllable growth of diamond film surface morphology was studied in a new 10kW MPCVD device. The experimental results show that the change of methane concentration may have a significant effect on the orientation, mass, nucleation density and growth rate of diamond films when the substrate temperature is fixed. At the same temperature, the growth of diamond films with higher methane concentration changes from 111 orientations to 100 orientations. The quality of diamond film increases with the decrease of methane concentration. When methane concentration is 2.0%, the surface morphology of diamond film is not sensitive to substrate temperature when methane concentration is 2.0%, which indicates that the surface morphology of diamond film is not sensitive to substrate temperature when methane concentration is moderate. At the same time, this phenomenon also shows that the process parameters of preparing highly oriented diamond films have a wide range of selection at medium concentration of methane. According to the practical problems encountered in the experiment, the existing 10k W-MPCVD device has been improved. The antenna structure, water cooling system and airflow distribution in the cavity are improved reasonably. Firstly, the loudspeaker structure, which is difficult to be machined, is changed into a vertical structure to obtain a stable large size plasma sphere. Secondly, the water cooling system of the device is improved, and the water cooling system of the water cooled substrate is divided into different regions, so that the water cooling effect from the central area to the edge area of the substrate is gradually reduced, and a more uniform temperature distribution is obtained on the substrate. Finally, the flow direction of the gas in the cavity is improved, so that the reactive gas can flow more through the plasma region and improve the utilization efficiency of the reaction gas. Through the above research, we have mastered the general law of the deposition of CVD diamond films by various technological parameters on the new 10k W-MPCVD device, which provides a good experimental basis for the preparation of CVD diamond films with high orientation and high quality. At the same time, the device is further improved and successfully discharged. It provides a new excellent platform for the further study of high quality and high orientation diamond films.
【学位授予单位】：武汉工程大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ163;TB383.2

【相似文献】