Property Control of Diamond-like Carbon Thin Films Synthesized by High Density Plasma

近年来，人们用各种方法合成了多种类型的金刚石和类金刚石。然而，合成的薄膜的性质、sp2/sp3键的比例以及它们与合成条件之间的关系尚不清楚。在本研究中，我们研究了合成条件对薄膜的比例和物理化学性质的影响。采用为空间推进器开发的MPD Arc-Jet(磁等离子体动态电弧-Jet)进行合成，其原因如下：(1)仅使用氢化碳气体就可以产生等离子体；(2)可以很容易地将合成铜薄膜和产生脉冲电子束的设备连接到MPD Arc-Jet上。结果表明，可以通过控制衬底温度、衬底偏压和所谓的CF4气体原位修饰来控制比例。通过改变比例、密度、硬度和电导率可以控制。在碳的冲击处理和电爆炸碳等离子体的研究中，在与铜共存的情况下，很容易实现石墨碳向金刚石的转变。铜通常充当一个热槽，然而，它似乎真的充当了外延生长的衬底。因此，这一假设适用于MPD Arc-Jet的合成：石墨层夹在MPD Arc-Jet合成的两个铜层之间，脉冲电子束暴露在三明治型薄膜中。用拉曼光谱可以探测到只有sp^3键的小范围内的粒子。我们必须推进这项技术，并研究铜在这种转变中的作用。我们都感谢G.Burkhard博士在合成材料等方面的帮助。

Recently, many types of diamond and diamond-like carbons are synthesized by various methods. However, the properties of the synthesized thin films, the ratio of sp^2/sp^3 bonds and also the relationship between the properties and the synthesis condition are still remained unclear.In this study, we concerned the effect of synthesis condition on the ratio, physical and chemical properties of the films. MPD Arc-Jet (Magneto Plasma Dynamic Arc-Jet), which was developed for the space thruster, was used for the synthesis, because of the following reasons : (1) It can produce plasma using only pure hydro carbon gases, (2) Equipment for synthesizing copper thin films and producing a pulsed electron beam can be attached to the MPD Arc-Jet easily.Summarizing the results as follows ; the ratio can be controlled by controlling the substrate temperature, bias potential of the substrate, and also so-called in situ modification using CF_4 gas. By changing the ratio, density, hardness and electrical conductivity can be controlled.In a research for shock treatment of carbon and for carbon plasma by electrical explosion, transformation of graphite carbon into diamond was realized easily in a case of coexisting with copper. Copper usually act as a heat tank, however, it really seems to act as a substrate for epitaxy growth. Therefore, this hypothesis is applied to this synthesis in MPD Arc-Jet : graphite layr is sandwiched between two copper layrs synthesized by MPD Arc-Jet and a pulsed electron beem is exposed to the sandwiches type films. Particles, in a small area, consisting with only sp^3 bond canbe detected by Raman spectroscopy.We have to advance this technique and research the role of copper in this transformation.We all thank Dr.G.BURKHARD for his grate assistance in synthesizing materials, etc.