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Predicting the occurrence of unintended gas breakdown in narrow gaps within plasma processing chambers is essential for the development of future plasma sources in the semiconductor industry. This study[1] conducted experimental and theoretical analyses focusing on the unexpected discharge events in narrow gaps. We observed a notable drop in the gas breakdown voltage when exposed to an existing background plasma facing the gap. Kinetic simulations suggest that a much higher initial current leaking from the plasma into the gap enhances the electric field. This results in a greater ionization rate, thus reducing the required voltage for breakdown. Furthermore, experimental results showed that the breakdown voltage decreases after several breakdown events. The eroded wall tends to increase the secondary electron emission, thus increasing the ionization and lowering the breakdown voltage. Preventing wall erosion due to the first discharge is therefore crucial to mitigate this undesired effect.
[1] Son, S. H., Go, G., Villafana, W., Kaganovich, I. D., Khrabrov, A., Lee, H.-C., Chung, K.-J., Chae, G.-S., Shim, S., Na, D., & Kim, J. Y. (2023). Unintended gas breakdowns in narrow gaps of advanced plasma sources for semiconductor fabrication industry. Applied Physics Letters, 123(23), 232108. https://doi.org/10.1063/5.0172566
