| Abstract
| - F−-encaged material C12A7-F− was synthesized and used as a pure F− emitter. The species emitted from the material were dominated by F− anions (about 90%) in a current density of 10 µA/cm2 level. Pure and stable F− anions are useful for materials etching.
- The present study provides a novel approach to produce pure and stable atomic fluorine anions (F−) in the gas phase by using the F− storage emission material of [Ca24Al28O64]4+·(O2−)0.35(F−)3.30 (abbreviated as C12A7-F−), synthesized by the solid-state reaction of CaF2, CaCO3, and γ-Al2O3. The anionic species stored in the C12A7-F− material were dominated by the F− anions, about (1.9 ± 0.3) × 1021 cm−3, accompanied by a small amount of O2−, O−, and O2−, via ion chromatography and electron paramagnetic resonance measurements, which corroborates that the anionic species emitted from the C12A7-F− surface were dominated by the F− anions (about 90%) together with a small amount of the O− anions and electrons, identified by a time-of-flight mass spectroscopy. The absolute emission current density of F− was sensitive to the surface temperature and extraction field, reaching about 16.7 ± 0.8 µA/cm2 at 800 °C and 1200 V/cm. A pure and stable atomic fluorine anion beam was developed by using an electrochemistry implantation method. Particularly, the atomic fluorine anions were found to be useful for the etching of Si and SiO2, evaluated by the morphological alterations via a field emission scanning electron microscope, and the surface composition’s changes using X-ray photoelectron spectroscopy.
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