Fundamental Study on a Synthesis Apparatus of Transparent Diamond Films by Chemical Vapor Deposition

采用适合高速合成的电弧放电等离子体气相沉积法合成金刚石薄膜。然而，这种方法有缺点，如金刚石薄膜的厚度和质量分布。为此，设计并研制了一种新型的磁场控制等离子体状态的装置，以研究磁场对沉积金刚石薄膜形状和质量的影响。磁场作用于甲烷、氢气和氩气产生的等离子体射流，使等离子体射流直径增大，厚度和质量的分布得到改善。讨论了制备透明金刚石薄膜的沉积条件。在较低的甲烷浓度（1%）下获得了高透光率的金刚石膜，与成核密度无关。用FTIR测量了金刚石砂轮抛光后的金刚石膜的透光率，在10mum波长处透光率约为68%。通过x射线衍射分析发现，该透明金刚石膜具有随机取向，通过观察其截面结构发现其缺陷和杂质较少。由于在确定的沉积条件下合成厚的透明金刚石膜需要很长时间，因此CVD设备需要产生稳定且长寿命的等离子体射流。

Diamond films were synthesized by arc discharge plasma jet CVD that is suitable for high rate synthesis. However, this method has drawbacks such as distributions of thickness and quality occurs in diamond films. Thus, the plasma state were controled by magnetic field with a newly type of an apparatus that were designed and developed in order to study the effect of magnetic field on the shape and quality of diamond films deposited. As a result of application of magnetic field to plasma jet generated with methane, hydrogen and argon gases, the diameter of a plasma jet increases and the distributios of thickness and quality are improoved.The deposition conditions were also discussed for synthesizing transparent diamond films. Diamond films that have high transmittance are obtained at lower methane concentration of 1% independen of nucleation density. Transmittance of the diamond film that polished with diamond wheel was measured with FTIR and was approximately 68% at the wavelength of 10mum. This transparent diamond film was found to have random orientation by X-ray diffraction analysis and less defects and impurities by the observation of the structure of its cross section. As it takes long time to synthesize thick transparent diamond films under the determined deposition conditions, CVD apparatuses need to generate a stable and long-life time plasma jet.