Plasma based processes are used in technologies such as the fabrication of very-large-scale-integrated (VLSI) micro-electronic devices. A plasma reactor consists of a wafer placed between two electrodes (one powered and one grounded). The plasma flows through the annulus and etching and deposition of films is accomplished by ions that are accelerated towards the wafer in conjunction with neutrals that diffuse to the wafer. Volatile reaction products diffuse back into the bulk of the plasma where they participate in a complex chain of collision processes. Two areas about which more information is needed are the surface of the wafer where the etching and deposition occur and the plasma where the reactive species are produced. The PI is interested in elucidating the processes that occur in the plasma and using that information to increase understanding of the plasma-surface interaction including the flux and nature of the species that impinge on the surface. Reactive plasma constituent are produced from inert feed gases by various electron collision processes. This grant will supply funds to enable the PI to build a versatile corrosion-resistent electron-impact fragment spectrometer that will allow a comprehensive study of the electron impact dissociation of those key industrial gases that are currently employed in low temperature processing plasmas. The instrument will be equipped with diagnostic tools (eg. optical spectroscopy, time-of-flight (TOF) and TOF-mass spectroscopy, and laser-induced-flourescence spectroscopy) to measure absolute cross sections and appearance potentials for the formation of radiating, metastable and neutral as well as charged ground-state fragments produced by dissociative electron impact. The experimental results will be used to predict and optimized the performance characteristics of a discharge device which will ultimately be used in the design, operation and control of novel plasma processing reactors.
