Diagnostic studies of ablation plumes generated by a channelspark electron beam

Abstract

Summary form only given. The ablation of materials by a channel-spark electron beam is being studied. Channel-spark electron beam ablation is applied to the deposition of thin films. The channel-spark is a high current/low accelerating voltage electron beam device developed at KFK in Karlsruhe, Germany. It is a pseudospark device that operates in the ion focused regime. The channel-spark has the following parameters: electron beam current of 1.5 kA, accelerating voltage of 15-20 kV, background argon gas pressure of 5-20 mTorr. Ablation targets have consisted of metals (Fe, Ti), a conducting compound (TiN), and an insulating compound (SiO/sub 2/). Channel-spark ablation plumes have been studied spectroscopically, both by wavelength-resolved, time-integrated, gated spectroscopy and by time resolved monochromator spectroscopy. These spectroscopic studies have yielded information about the ionization state of both the ablated plume material and the argon background gas. Plumes of target material consist of neutral, singly ionized and doubly ionized species. Ion focusing plasmas contain doubly and triply ionized argon. Non-perturbing dye laser diagnostic experiments on the ablation plume are now beginning. These include laser light scattering by particulate and dye laser resonance absorption photography of ablated plume species. Preliminary film deposition experiments have also started. Effects of space charge buildup on insulating targets have been observed.