Elementary Steps in Plasma Chemistry

在实验物理化学项目的这个项目中，马里兰大学的约翰·摩尔和约翰·托塞尔将研究电子-分子碰撞的过程。这些过程包括：解离电子附着，产生一个自由基和一个负离子；直接解离，产生两个自由基；偶极解离，导致同时产生一个正离子和一个负离子；解离电离，生成一个离子和一个自由基。该项目涉及这些过程的实验和理论表征，因为它们发生在气相和表面上。选择用于研究的系统包括卤代烃、卤代硅烷、卤代烯烃和卤代氟碳化合物。这些前体及其产物被认为对理解等离子体反应器（如用于等离子体蚀刻和半导体器件制造的反应器）中涉及的化学至关重要。气体中的放电产生一个富电子的环境，在通常不反应的气体中引起化学变化。这种高度带电的混合物被称为等离子体，发生的化学反应被称为等离子体化学。这种反应器在半导体工业中被广泛用于制造材料和器件。这项研究将提供有关参与这些反应的物种性质的详细信息，以及它们的反应的基本知识。

In this project in the Experimental Physical Chemistry Program, John Moore and John Tossell of the University of Maryland will investigate the processes involved in electron-molecule collisions. Such processes include: dissociative electron attachment, yielding a radical and a negative ion; direct dissociation, resulting in two radicals; dipolar dissociation, resulting in the simultaneous production of a positive and a negative ion; and dissociative ionization, yielding an ion and a radical. The project involves both experimental and theoretical characterization of such processes as they occur in the gas phase as well as on surfaces. Systems chosen for study include halocarbons, halosilanes, halogenated alkenes, and halofluorocarbons. These precursors and their products are thought to be crucial in understanding the chemistry involved in plasma reactors such as those used for plasma etching and in the fabrication of semiconductor devices. An electrical discharge in a gas creates an electron-rich environment which induces chemical changes in normally unreactive gases. This highly charged mixture is known as a plasma, and the chemical reactions taking place are termed plasma chemistry. Such reactors have found widespread use in the semiconductor industry for fabrication of both materials and devices. This research will provide detailed information on the nature of the species involved in such reactions, as well as fundamental knowledge of their reactions.