微波等离子体技术制备金刚石膜的工艺研究

发布时间：2018-06-22 23:42

  本文选题：金刚石膜 + 微波等离子体化学气相沉积　； 参考：《昆明理工大学》2017年硕士论文

【摘要】：金刚石膜具有优异的物理化学性能,如热膨胀系数和摩擦系数低、禁带宽度大、耐磨性优良、红外线透过率高、生物兼容性好,在光学、电学、生物学、机械领域具有广泛的应用前景,其制备工艺和功能化应用已成为当前材料科学研究的前沿热点。然而,高质量大尺寸金刚石膜是战略产品,在制备技术和产品受国外垄断的背景下,本文采用微波等离子体化学气相沉积方法,以自主研制的MPCVD装备为工具,通过优化工艺条件,实现了对金刚石膜纯度、晶相结构、生长速率、晶体粒径、表面质量的调控,并探讨了金刚石膜的生长机制和辅助气体的协同作用机理。采用自主研发的3 kW/2450MHz型微波等离子体化学气相沉积系统,以单晶硅(100)为基体材料,分别研究了基体温度、反应腔体压强和甲烷浓度对金刚石膜纯度及生长速率的关联规律,并采用响应曲面优化设计确定了金刚石膜的最优工艺参数组合:基片温度为837 ℃,甲烷/氢气相对浓度为2%,反应腔体压强为6.95kPa,在此条件下金刚石膜的生长速率为0.378 μm/h,金刚石相含量由84.7%提升至89.5%。在获得CH4/H2体系最优制备工艺的基础上,开展了氧、氩辅助气体调节金刚石膜的生长行为探索。研究了不同氧-氩混合组分构成对微米级金刚石膜表面质量的协同调控规律,发现O2:Ar流量组合为1 sccm:14 sccm时,金刚石膜的表面粗糙度最低(约81.5 nm),金刚石相纯度为86.1%;同时研究了 O2流量与超纳米级金刚石膜的生长关联规律,结果表明:O2流量低于0.5 sccm时,O2促进晶粒生长的作用占主导地位;O2流量高于0.5 sccm时,O2促进二次形核的作用占主导地位。在获得CH4/H2传统原料制备金刚石膜的工艺以后,发现该原料组合体系存在易燃易爆风险,针对该问题本论文开展了无氢气直接参与的原料体系制备金刚石膜的工艺探索,创新性地采用甲醇-氩气体系成功制备出金刚石膜。研究表明:金刚石膜以(111)晶面择优生长,金刚石相含量达75.71%,未发现石墨相存在。在探明纯金刚石膜制备适应性工艺的基础上,开展了硼掺杂金刚石膜的制备工艺研究。采用氧化硼-乙醇溶液为硼源成功制备出的硼掺杂金刚石膜,样品均呈现(111)晶面择优生长,结晶度和成膜质量良好。少量硼元素有利于提高金刚石膜颗粒的均匀性,当氢气鼓泡流量为3 sccm时,硼掺杂金刚石膜的晶粒一致性最佳,电势窗口为3.1V,且电化学可逆性良好。
[Abstract]:Diamond film has excellent physical and chemical properties, such as low coefficient of thermal expansion and friction, wide band gap, excellent wear resistance, high infrared transmittance, good biological compatibility, and good optical, electrical, biological, The preparation technology and functional application of machinery have become a hot research field in material science. However, the high quality and large size diamond film is a strategic product. Under the background that the preparation technology and products are monopolized by foreign countries, the microwave plasma chemical vapor deposition (MPCVD) method is adopted in this paper, and the self-developed MPCVD equipment is used as the tool. By optimizing the process conditions, the growth mechanism of diamond film and the synergistic action mechanism of auxiliary gas were discussed, which can control the purity, crystal phase structure, growth rate, grain size and surface quality of diamond film. The dependence of substrate temperature, pressure of reaction chamber and concentration of methane on the purity and growth rate of diamond film was studied by using a 3 kW / 2450MHz microwave plasma chemical vapor deposition system with single crystal silicon (100) as substrate material. The optimum process parameters of diamond film are determined by the optimum design of response surface. The substrate temperature is 837 鈩，

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