Analysis of Interfacial Phenomena between Plasmas and Solid Surfaces with Microstructure

首先，自由基从等离子体传输到衬底的流量被测量作为表面反应的边界条件。所测量的自由基包括H、O、N等原子物种和SiH_2、CF_2等分子物种。其次，发展了一种新的原位表面诊断方法--傅立叶红外相位调制椭圆偏振光谱法（PMSE），该方法可以高灵敏度地检测表面的化学键合状态，并首次应用该方法研究了硅片腐蚀过程中的表面反应。一个薄的氟化overlayr上检测到放置在自偏置RF电极，这是由离子轰击与可观的能量，除了中性自由基照射的基板。另一方面，在放置在接地电极上的基板上观察到聚合物形成，离子轰击较少。这些现象被认为分别发生在图案化衬底上的微沟槽的底部和侧壁处。在另一个例子中，我们研究了SiH_2和H自由基在非晶和多晶Si薄膜沉积中的作用。用原位椭圆偏振光谱仪分析了沉积膜的特性。作为一个重要的结论，人们已经认识到，氢原子在非晶组织的蚀刻和应力结构的化学退火，以促进晶体生长的工作。通过这些研究，一些方法已被认为是提高空间分辨率的气相和表面诊断。随着分辨率的提高，该项目继续进行，以更好地理解等离子体与微结构衬底的相互作用。

Firstly, fluxes of radicals transported from plasmas to substrates were measured as the boundary condition for surface reactions. The radicals measured are including atomic species such as H,O and N,and molecular species such as SiH_2 and CF_2. Secondly, a new method named FT-IR phase modulated spectroscopic ellipsometry (PMSE) has been developed for in-situ surface diagnostics By this method chemical bonding states on the surface are detected with a high sensitivity.By using these method, surface reactions in the etching of Si wafer was investigated as the first example. A thin fluorinated overlayr was detected on a substrate placed on the self-biased RF electrode, which was irradiated by ions bombarding with appreciable energy in addition to neutral radicals. On the other hand, polymer formation was observed on a substrate placed on the grounded electrode with less ion bombardment. These phenomena are suggested to occur at the bottom and the side wall, respectively, of a micro-trench on a patterned substrate. The effect of ion bombardment are going to be investigated in detail by using a mass spectrometer placed at the bottom of a substrate with micro channels of high aspect ratios.In the other example, roles of SiH_2 and H radicals were studied in the deposition of amorphous and polycrystalline Si films. The characteristics of deposited films were analyzed by in-situ spectroscopic ellipsometry. As an important conclusion, it has been recognized that hydrogen atoms work both in the etching of amorphous tissue and in the chemical annealing of stressed structures for enhancing the crystal growth.Through these studies some methods have been considered for increasing the spatial resolution in the gas-phase and surface diagnostics. With the improved resolution this project has been continued for better understandings of the interaction of plasmas with micro-structured substrates.