STUDIES ON MEASUREMENTS OF RADICALS IN GAS PHASE USING SPECTROSCOPY TECHNIQUES

(1)利用红外半导体激光吸收光谱技术和各种激光光谱技术研究了等离子体源激发的CFx（X = 1 -3）、SiHx（X=1-3）和Si自由基，阐明了自由基的行为。发展了控制CFx（X=1-3）自由基密度和组成的技术。(2)得到了一组反应性分子在电子碰撞下解离成中性自由基的交叉作用数据。当离子入射到表面上时，测量从表面解离散射的离子种类。阐明了刻蚀过程中CF_2自由基的表面反应。(3)采用激光荧光技术，即205 nm双光子激发，测量了平行板射频硅烷等离子体中H自由基的密度，阐明了H自由基的行为。(4)本文研究了氢自由基在低温多晶硅膜形成中的作用，阐明了氢自由基的重要作用。利用相位调制傅里叶变换红外光谱仪对暴露于CF_4等离子体中的Si表面进行了观察。结果表明，颗粒在甲烷等离子体中通过静电力和/或吸引力生长，并形成颗粒的空间排列。这种伪二维排列的机制进行了研究。(5)利用激光和探针技术研究发现，短寿命自由基是促进粒子成核的关键物种，尤其是SiH_2，它们多次参与了初始生长过程。(6)空间和时间分辨发射光谱被应用于获得在电容耦合等离子体的等离子体结构的行为的信息。研究发现，随着耗散功率的增加，鞘层宽度增加。此外，还证实了在O_2等离子体中，O与O^-反应中的协同效应大量产生。

(1) CFx (X=1-3), SiHx (X=1-3) and Si radicals in plasmas excited by some plasma sources were investigated by infrared diode laser absorption spectroscopy and various kinds of laser spectroscopy technologies, and the behaviors of radicals was clarified. The techniques to control the density and compositon of CFx (X=1-3) radicals were developed.(2) A set of cross action data on electron-impact dissociation of reactive molecules into neutral radicals was obtained. Ionic species dissociatively scattered from the surface were measured when the ions were incident on the surface. The surface reaction of CF_2 radicals for etching processes were clarified.(3) The density of H radicals in a parallel plate RF silane plasma were measured by laser fluorescence technique, namely two-photon excitation at 205nm and the behavior of H radicals was clarified.(4) The role of H radicals in the formation of poly-crystalline Si films at a low temperature was investigated and it was clarified that H radicals playd an important role. The surface of Si exposed to CF_4 plasma was observed by phase-modulated FT-IR spectroscopy developed in this study. It was found that the particles grew through electrostatic forces and/or attractive force in the methane plasma and the spatial arrangement of particle was formed. The mechanism of this pseudo two-dimensional alignment was investigated.(5) It was found that the key species contributing to the particle nucleation were short-life radicals, especially SiH_2 and they participated many times in the initial growth process using laser and probe techniques.(6) Space-and time-resolved emission spectroscopy was applied to obtain the information on the behavior of the plasma structure at a capacitively coupled plasma. It was found that the sheath width increased with increasing the dissipated power. Moreover, it was confirmed that the synergism in the reaction between O and O^- produced in abundance in O_2 plasma.