Studies on surface reaction process and thin film formation by controlling radicals

在本项目中，我们首先系统地研究了在硅烷/氢混合气体中ECR等离子体中沉积薄膜的结晶度与气相信息之间的关系。结果发现，离子通量的降低有助于结晶度的提高。在此基础上，我们发展了一种新的无离子物种沉积薄膜的方法，即只使用中性物种的永磁体。用这种方法，我们成功地合成了结晶度高、表面光滑的多晶薄膜。然而，沉积速度被降低到使用传统方法的十分之一。为了解决这个问题，我们尝试了一种新的两步生长方法。在该方法中，利用永磁体在生长的初始阶段去除离子物种。在此步骤之后，从等离子体中去除永久磁体，使用常规的ECR硅烷/氢等离子体沉积薄膜，n…更常见的包括离子和中性物种。因此，我们成功地合成了结晶度高、表面光滑、沉积速率较高的薄膜。此外，我们还发现了离子物种对晶相形核的干扰作用。在金刚石的形成过程中，我们利用真空紫外吸收光谱和光学发射光谱，从薄膜质量与自由基行为的相关性中阐明了自由基的作用。因此，碳原子促进了非金刚石相的形成，而OH自由基促进了终止于金刚石表面的氢原子的提取反应。在1996-1998年的这个项目中，我们通过阐明多晶硅和金刚石薄膜形成过程中的作用，成功地获得了重要的发现。此外，在此基础上，我们成功地开发了通过控制自由基来获得质量更好的薄膜的方法。较少

In this project, firstly we investigated systematically the correlation between the crystallinity of the deposited films and the information of gas phase in ECR plasma using silane / hydrogen mixture gases. As a result, we found that the reduction of ion flux contributed to the improvement of the crystallinity. On the basis of this result, we developed a novel method for depositing films without ionic species, namely, only neutral species using permanent magnets. Using this method, we have successfully synthesized the polycrystalline films with high crystallinty and smooth surfase. However, the deposition rate was reduced to be a tenth of that using the conventional method. To solve this problem, we have tried a novel two step growth method. In the method, ionic species were removed at the initial growth stage by using permanent magnets. After this step, the permanent magnets were removed from the plasma, the films were deposited by using the conventional ECR silane/hydrogen plasma., n … More amely including ionic and neutral species. As a result, we have successfully synthesized the films with high crystallinity, smooth surface and relatively high deposition rate. Moreover, we have found that ionic species disturb the nucleation of the crystalline phase especially.In a diamond formation process, we have clarified the role of radicals from the correlation between the film quality and the behaviors of the radicals using vacuum ultraviolet absorption spectroscopy and optical emission spectroscopy. As a result, carbon atom contributes to the formation of non-diamond phase while OH radical promotes the abstraction reaction of hydrogen atom terminating the diamond surface.In this project from 1996 to 1998, we have successfully obtained important findings by elucidating the roles in the polycrystalline silicon and diamond film formation processes. Moreover, on the basis of the findings, we have successfully developed the methods promising to obtain the films with further better quality by controlling the radicals. Less