MPCVD法制备大面积纳米金刚石薄膜的研究

发布时间：2018-07-04 08:06

  本文选题：改进型MPCVD装置 + 均匀性　； 参考：《武汉工程大学》2015年硕士论文

【摘要】：金刚石拥有优异的物理化学性质,因而作为新型材料具有极其广阔的发展前景。化学气相沉积法(Chemical vapor deposition,CVD)作为成膜质量性能堪比天然金刚石的优良特性受到了各领域的广泛关注。在诸多方式中,微波等离子体化学气相沉积法(Microwave Plasma Chemical Vapor Deposition,MPCVD)因其独特的无极放电低污染模式、等离子体能量高度集中等优势成为高质量大面积金刚石膜沉积时的最佳选择。目前国内金刚石膜沉积方面的研究,主要受到大面积MPCVD沉积设备及相关工艺参数的系统研究所限,在此领域获得突破较少。本论文利用实验室自制的10kW MPCVD装置,系统研究各项工艺参数对薄膜沉积质量、均匀性等指标的相关影响,并根据所获得结果对装置结构、实际最佳工艺参数进行改进和总结,为高质量大面积金刚石膜的实用化提供了实验依据。在本次研究过程,首先对各项工艺参数进行了综合研究,通过对比不同微波功率、沉积气压下基片的温度,确认了改进型装置对均匀成膜的有力帮助,同时掌握微波功率与气压对基片温度、等离子体均匀性的影响关系;并以此为基础比较不同甲烷浓度与微波功率下金刚石膜的沉积速率,结果表明提高甲烷浓度与微波输出功率均能有效地提升金刚石膜的沉积速率,且在甲烷浓度超过1%、基片温度超过850℃处存在明显转折点。通过归纳实验所得数据总结出最佳工艺参数,并成功制备了均匀性较好的直径达到100mm的大面积金刚石膜。其次,通过对比实验初步地研究引入辅助气体对金刚石膜沉积过程的影响。实验结果表明在所选工艺参数下引入少量氧气可以使金刚石膜的质量大幅提高,同时沉积速率与取向性都有所提高;引入少量二氧化碳可显著提高薄膜的沉积速率,但表面均匀性明显受到影响;而引入少量氮气则会抑制晶粒生长并显著促进二次形核。最后系统地研究不同浓度混合比的氮氧混合气体对金刚石膜生长的影响,发现氮氧混合气体对金刚石膜生长的影响主要由其中浓度较高的组分决定,即氮气浓度较高时主要表现出抑制生长与促进二次形核,而氧气浓度较高时主要表现为提高成膜质量与取向性;在此基础上尝试利用实验所获得的结果进行薄膜制备,在适当的工艺参数下成功获得了有一定均匀性的大面积纳米金刚石膜。尝试性使用四探针方块电阻测试仪,对所得纳米级金刚石膜均匀性进行了定性检测,并发现测定结果准确性易受基片条件、结合程度与薄膜沉积厚度的影响。
[Abstract]:Diamond has excellent physical and chemical properties, so it has a broad development prospect as a new material. Chemical vapor deposition (CVD) as a film forming quality property comparable to the excellent properties of natural diamond has received extensive attention in various fields. In many ways, microwave plasma chemical vapor deposition (MPCVD) is the best choice for high quality and large area diamond film deposition due to its unique low pollution mode of electrodeless discharge and high concentration of plasma energy. At present, the research on diamond film deposition in China is mainly limited by the systematic research of the large area MPCVD deposition equipment and related technological parameters, but there are few breakthroughs in this field. In this paper, a 10kW MPCVD device made by the laboratory is used to systematically study the influence of various technological parameters on the quality and uniformity of the film deposition. According to the obtained results, the structure of the device and the practical optimum process parameters are improved and summarized. It provides experimental basis for the practical application of high quality large area diamond films. In this research process, various technological parameters are studied comprehensively. By comparing different microwave power and temperature of substrate under deposition pressure, it is confirmed that the improved device has the force to help uniform film formation. The effects of microwave power and pressure on substrate temperature and plasma homogeneity were studied, and the deposition rates of diamond films with different methane concentrations and microwave power were compared. The results show that both methane concentration and microwave output power can effectively increase the deposition rate of diamond films, and there is an obvious turning point when methane concentration exceeds 1 and substrate temperature exceeds 850 鈩，

本文编号：2095399