Collision Cross Sections for Electron-Impact Dominated Processes in Etching Plasmas

等离子体蚀刻和等离子体增强化学气相沉积等基于等离子体的工艺被用于微电子器件的制造。用于设计和控制目的的系统模型需要一个“冷”等离子体中各种物质的基态和激发态密度的微观数据库。物理参数，如气体混合物，气体压力，功率沉积，流速和反应器几何形状需要确定等离子体的特性。电子碰撞是等离子体初始击穿的主要过程。解离和/或电离电子碰撞起着关键作用，因为它们产生了负责蚀刻和沉积的物质。建立一个全面的数据库，包括电子碰撞截面的实验数据，将有助于等离子体过程的建模和设计。侦探的计划，研究离解和电离电子与处理等离子体的活性成分的碰撞，以及它们分裂后产生的稳定自由基，沿着三条线：(1)激光诱导荧光（LIF）研究中性基态碎片的形成，使用电子束/气体束/激光束装置来确定中性基态解离形成的绝对截面和外观电位碎片。(2)电离和解离电离过程的研究-绝对电离截面，外观电位，质谱裂解模式-使用交叉快原子束/电子束装置。(3)利用上述装置进行解离碎片能量亚稳形成的飞行时间研究。

Plasma based processes such as plasma etching and plasma enhanced chemical vapor deposition are used in the fabrication of microelectronic devices. Models of the system, used for design and control purposes, require a microscopic data base of the ground and excited-state densities of the various species in a "cold" plasma. Physical parameters such as the gas mixture, gas pressure, power deposition, flow rate and reactor geometry are needed to determine the characteristics of the plasma. Electronic collisions are the dominant processes in the initial breakdown of the plasma. Dissociative and/or ionizing electron collisions play a pivotal role, since they produce the species that are responsible for the etching and deposition. Building a comprehensive data base, including experimentally derived data on electron collision cross sections, will help in the modelling and design of plasma processes. The P.I.'s plan to study dissociative and ionizing electron collisions with the reactive constituents of processing plasmas, and the stable radicals resulting from their break- up, along three lines: (1) Laser-induced fluorescence (LIF) studies of the formation of neutral ground-state fragments using an electron beam / gas beam / laser beam apparatus set up to determine the absolute cross sections and appearance potentials for the formation of neutral ground-state dissociation fragments. (2) Studies of ionization and dissociative ionization processes- absolute ionization cross sections, appearance potentials, mass spectral cracking patterns - using a crossed fast atomic beam / electron beam apparatus. (3) Time of flight studies of energetic metastable formation of dissociation fragments using the above apparatus.