Consequences of simultaneous exposure of inorganic solids to excimer laser light and an electron beam

Journal Article · Wed Aug 15 04:00:00 EDT 1990 · Journal of Applied Physics; (USA)

DOI:https://doi.org/10.1063/1.346618· OSTI ID:6550989

Dickinson, J T; Langford, S C; Jensen, L C; Eschbach, P A ^[1]; Pederson, L R; Baer, D R ^[2]

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1. Department of Physics, Washington State University, Pullman, WA (USA)
2. Pacific Northwest Laboratory, Richland, WA (USA)

In previous work we examined the changes in surface topography of sodium trisilicate glass (Na{sub 2}O{center dot}3SiO{sub 2}) with exposure to pulsed 248-nm excimer laser light at fluences of 2.6--5 J/cm{sup 2} (per laser pulse), as well as the character of the products emitted from the glass surface (e.g., {plus minus} ions, electrons, ground state and excited neutral atoms and molecules). At fluences above a threshold, ablative etching occurs only after a number of preliminary laser pulses. In this work, we show a dramatic synergism in the ablation process by simultaneous bombardment of the glass surface with 0.5--2 keV electrons {ital and} laser pulses. Extensive etching can be initiated immediately and sustained indefinitely at subthreshold fluences. Reflection electron energy loss spectroscopy performed on electron-bombarded surfaces shows band gap states growing with exposure. We propose that surface and near-surface defects produced by inelastic scattering of the electron beam provide single-photon absorption centers, facilitating etching at subthreshold fluences. The potential for single-photon driven etching/ablation of other wide band gap dielectric materials is also discussed. These studies also support the hypothesis that etching and damage of such surfaces can occur after prolonged exposure to laser irradiation alone due to an accumulation of absorption centers.

• DOE Contract Number: AC06-76RL01830
• OSTI ID: 6550989
• Journal Information: Journal of Applied Physics; (USA), Journal Name: Journal of Applied Physics; (USA) Vol. 68:4; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ABLATION
ALKALI METAL COMPOUNDS
BEAMS
ELECTROMAGNETIC RADIATION
ELECTRON BEAMS
ENERGY GAP
ENERGY RANGE
ENERGY-LEVEL DENSITY
ETCHING
EXCIMER LASERS
GAS LASERS
GLASS
KEV RANGE
KEV RANGE 01-10
LASER RADIATION
LASERS
LEPTON BEAMS
OXYGEN COMPOUNDS
PARTICLE BEAMS
PHYSICAL RADIATION EFFECTS
PULSES
RADIATION EFFECTS
RADIATIONS
SILICATES
SILICON COMPOUNDS
SODIUM COMPOUNDS
SODIUM SILICATES
SURFACE FINISHING