A wide area windowless plasma disk excited by a soft vacuum electron beam provides a wide area uniform source of vacuum ultraviolet (VUV) photons as well as atomic radicals. Hydrogen and oxygen when excited by the soft vacuum electron beam, emit strong atomic resonance radiation at 121.6 and 130 nm, respectively; in fact up to 8% of the total applied discharge power is emitted as VUV photons. The spatial uniformity of the atomic VUV resonance radiation approaches 6% across a disk 19 cm in diameter. The density of atomic oxygen species generated in the plasma disk has also been experimentally determined using an established polymer film etch rate method as well as with a conventional silver thin film sensor. We employ the disk plasma in a windowless configuration to achieve lower temperature chemical vapor deposition (CVD) than conventional thermal CVD. The VUV photon flux as well as the radical and excited atomic gas species emitted from the lamp can assist dissociation of feedstock reactant gases as well as assist heterogeneous surface reactions and increase surface mobility of absorbed species allowing for lower temperature CVD. Thin films of an aluminum nitride and hydrogenated amorphous silicon have been deposited at temperature between 100–400 °C. The deposited films show improvement over other plasma and photo‐assisted CVD processes in the film quality achieved, the area covered, the substrate temperature required, and the maximum deposition rates that are possible. In situ generation of arsine (AH3) and unsaturated arsenic hydrides AsHx (x≤2) have also been achieved by placing elemental arsenic in an environment rich in atomic hydrogen created from the disk–plasma source.
Wide area windowless disk plasma lamp of uniform intensity for use in microelectronic film processing
Z. Yu, T. Y. Sheng, B. Pihlstrom, Z. Luo, G. J. Collins; Wide area windowless disk plasma lamp of uniform intensity for use in microelectronic film processing. J. Vac. Sci. Technol. B 1 March 1991; 9 (2): 348–352. https://doi.org/10.1116/1.585573
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