Ž . Applied Surface Science 127–129 1998 947–952 Electron beam ablation versus laser ablation: plasma plume diagnostic studies S.D. Kovaleski, R.M. Gilgenbach ) , L.K. Ang, Y.Y. Lau, J.S. Lash 1 Intense Energy Beam Interaction Laboratory, Nuclear Engineering and Radiological Sciences Department, UniÕersity of Michigan, Ann Arbor, MI 48109-2104, USA Abstract Experiments have been performed to compare XeCl laser ablation plume characteristics to those produced by electron Ž . beam ablation. Potential advantages of electron beams include higher electrical efficiency ;30% , and the ability to process materials with high optical reflectivity or transparency. The electron beam is generated by a channelspark with parameters: peak voltage of 15–20 kV, current of 1.5–1.7 kA, and pulse length of about 200 ns. The electron beam is ion focused to about 2 mm diameter by an argon background gas. Initial diagnostic experiments have utilized optical emission spectroscopy to characterize the ionization dynamics of the ablation plumes of Fe targets. Spectra taken during electron beam ablation are composed of singly ionized iron, with negligible emission from neutral iron. This is in sharp contrast with XeCl excimer laser ablation, which is composed of both neutral and ion species, the neutrals persisting strongly after the laser pulse. In addition to Fe ion emission, the channelspark emission spectrum also exhibits a high degree of excitation and ionization of the Ar background gas. Strong emission from Ar q , Ar 2q , and Ar 3q has been measured. q 1998 Elsevier Science B.V. PACS: 52.40.yw; 52.75.Rx; 61.80.yx; 61.80.Ba Keywords: Electron beam; Electron beam ablation; Channelspark; Ablation plasma; Plasma spectroscopy 1. Introduction Pulsed ablative deposition has proven to be an important new process for thin films of hard-to-de- wx posit materials, such as cubic BN 1 and diamond- wx Ž . like carbon 2 . Excimer lasers KrF or XeCl have typically been utilized for ablative deposition. Ad- ) Corresponding author. University of Michigan, RM 1906, Cooley Bldg., 2355 Bonisteel Ave., Ann Arbor, MI 48109, USA. Tel.: q1-734-763-1261; fax: q1-734-763-4540; e-mail: rongilg@engin.umich.edu. 1 Now at Sandia National Laboratory. vantages of laser ablation include preservation of Ž . stoichiometry of compounds e.g., YBa Cu O 2 3 7yx wx 3 and generation of high energy ions which pro- wx mote film growth 1 . Low current electron beams wx have been employed by Dickinson et al. 4 to en- hance laser absorption by generation of defects in insulators. However, within the past several years, advances have been made in the technology of high current Ž . Ž . kA , moderate voltage 15–20 kV , channelspark w x electron beams 5,6 . The incident peak power den- Ž 9 2 . Ž sity ; 10 Wrcm and incident fluence 10–30 2 . Jrcm of these channelspark electron beams are 0169-4332r98r$19.00 q 1998 Elsevier Science B.V. All rights reserved. Ž . PII S0169-4332 97 00771-X